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4-1. Operations of the Switch

The preceding chapters have described what the AN/TTC-39 consists of and what it does. They also described the differences brought about by the modified switch, the AN/TTC-39A. This chapter explains how the AN/TTC-39 works. It also applies generally to the AN/TTC-39A, except for the structure of the TDSGM and the strapping of PCB. The last paragraph, 4-8, shows the additional data entry and display capabilities of the AN/TTC-39A.

Our perspective for the AN/TTC-39 is basically from the inside of the switch looking out. This chapter describes what takes place when a call enters, traverses, and exits the switch. It then will summarize the actions you take to set the switch up, turn it on, and bring it up to operating condition. Before the switch can process calls, however, it must recognize certain numbering schemes. The Army TTNP and other numbering plans with which the switch operates will be explained. You will learn how to implement planning orders from higher echelons to prepare the switch for processing calls. This will involve how to use planning and configuration worksheets. One of the most important things you will learn is how to design a circuit switch network and to provide the necessary information to switch personnel so that they may develop the switch data base. The chapter will also present a detailed description of how calls are routed through a network and how you can develop a routing plan for your own situation.

4-2. Traffic Switching and Processing

The AN/TTC-39 circuit switch can have many configurations. All of them, however, process and switch traffic in a similar manner. The fundamental difference between configurations is in the mix of analog and digital switching modules. The switch can connect analog and analog, digital and digital, and digital and analog subscribers. The switch also terminates analog and digital trunks, TGCs (for example, other AN/TTC-39 circuit switches and AN/TYC-39 message switches), digital switched groups, and supergroups (128/144 channels).

Analog switching.

The SDSG provides analog switching, supervising, and signaling. The SDSG functions in conjunction with the SCG, the CPG, the SPCG, and the CEG. Review Chapter 2 for descriptions of these. The key component of the SDSG is the SDMX where the switching occurs. The SDMX is an array of solid-state, silicon-controlled switches called cross points that connect circuits involved in analog switching. These circuits include external voice and data circuits and internal signaling and supervision circuits. All of them work together to process an analog call through the switch.

Each SDMX provides 156 inlets in 13 groups of 12 inlets each. The switch scans 120 of these 156 inlets for subscriber signals. The remaining 36 provide internal circuit connections. A basic shelter configuration could contain from one to four SDMXs, each of which contains up to 13 groups of 12 inlets. Thus, in a configuration of four SDMXs there may be a total of 624 inlets, of which 480 should be extranodal connections. The remaining 144 inlets can provide such service functions as tone sending or receiving, conference bridging, and intermatrix connections.

Digital switching.

The TDSG, in conjunction with the CEGs, provides digital switching, line termination, and signaling. The key component equipment of the TDSG is the TDMX where the switching occurs. (See Figure 4-l.) The switch converts all incoming signals to a 32-kbs pulse rate for digital processing. It then switches the 32-kbs subscriber pulse trains through a multistage multiplexing and demultiplexing chain into five 64-channel data streams. These data streams are routed to the TDMX which provides switching by transposing the incoming time-ordered bit locations to the outgoing bit locations of the called subscribers. The incoming bit locations correspond to the originating subscriber lines. This transposition occurs in the time division memory modules in the TDMX. (See Figure 4-l.)

The process is one of writing data into and reading data out of a single TDMM. (See Figure 4-2.) The process interchanges the information in selected time slots. As shown in the example in Figure 4-2, information arriving in time slot 63 transfers to time slot 2 in the outgoing data stream. Because full-duplex operation also requires the return connection, information arriving in time slot 2 must also transfer to time slot 63. Each 4-wire connection, therefore, requires two transfers of information.

Each TDMM provides access to sixty-four 4-wire terminations. A TDMX (or a TDSG) may consist of 3 to 5 TDMMs. (See Figure 4-l.) Thus, to connect a subscriber from one TDMM with a subscriber in a different TDMM, the switch must perform two functions. Not only must it interchange time slots between incoming and outgoing bit locations in a single data stream (as shown in Figure 4-2), but it must also switch the bit locations from one TDMM (from one data stream) to another. Figure 4-3 shows this process. As shown in this example, incoming information from subscriber 2 in TDMM 1 transfers to subscriber 10's outgoing time slot in TDMM 2. In the same way, an incoming call from subscriber 10 in TDMM 2 is connected to subscriber 2 by transferring subscriber 10's incoming information to subscriber 2's outgoing time slot in TDMM 1.

An AN/TTC-39 can have a maximum of 15 TDMMs. Table 4-1 lists TDMM assignments to TDSGs. It also shows the binary number (also called the bit select location) of each TDMM that corresponds to a MUX data stream. A fully populated digital switch would include all four TDSGs. Each TDSG uses the following TDMMs:

TDSG 1 uses TDMM numbers 1, 2, 3, 13, 14, and 18. (18 is a spare)

TDSG 2 uses TDMM numbers 4, 5, 6, and 15.

TDSG 3 uses TDMM numbers 7, 8, and 9.

TDSG 4 uses TDMM numbers 10, 11, and 12.

TDMX operation.

This paragraph describes the internal operation of a TDMM. (See Figure 4-4.) The TDMM performs the time division switching of multiplexed data streams that originate at the switch multiplexers (bit select numbers 1 through 15) or at the digital signal generators (bit select numbers 16 and 17). (See Table 4-l.)

Each TDMM contains a 64 x 17 bit data memory storage area for all subscriber address location data bits. The 64 columns correspond to the subscriber channels. The 17 rows correspond to the multiplexed data streams (or bit select numbers). Each TDMM also contains a 64 x 15 bit command memory storage area. This identifies originator and recipient address locations. The 64 columns correspond to the recipient subscriber channels. The 15-bit field consists of 5 bits for the call originator bit select location, 6 bits for the originator address location, and 4 bits for a parity check. Each TDMM contains all the logic necessary to connect it with the SCG and to interpret the connection and control commands from the processor. This enables it to perform its time division switching and memory check functions.

Figure 4-4 illustrates the call originator, subscriber number 131 (bit select number 3 or MUX 3, address location number 2 or channel 2), making a half connection call to recipient subscriber number 63 (bit select number 1 or MUX 1, address location number 62 or channel 62).

The switch multiplexer multiplexes each group of 64 subscribers into a single 64-channel, 2.048-mbs digital data stream. The data stream from each switch multiplexer passes to every TDMM where the 64 data bit positions (one for each subscriber) are stored in the data memory at the appropriate bit select location. In addition to a maximum of 15 data streams from the switch multiplexer, there are two 64-channel data streams from two digital signal generators. The digital signal generator output data streams also pass to every TDMM in the circuit switch. Thus, a fully populated circuit switch contains 15 TDMMs, each of which contains a 17 x 64 data memory. All the data memories are identical and contain an input data bit from every subscriber. For a complete listing of TDMX addresses available in a fully populated digital switch, see Table A-3.

The half-connection command from the processor designates both the originator and the recipient of the call. The TDMM that recognizes itself as the recipient (TDMM 1 in this case) stores the originator address (a 15-bit message including parity) in the command memory at the recipient location (one of the 0 to 63 columns). In this example, the command memory of TDMM 1 (bit select 1) at recipient address location 62 stores the originator's address (bit select 3, address location 2). If this were a full connect command, the command memory of TDMM 3 at recipient address location 2 would store bit select 1, address location 62.

The output selector synchronously reads the 64-recipient locations in the command memory to order the sequence of the time slots of the outgoing data stream. In this example, the selector reads recipient column 62 in the command memory. It determines (from the first five bits) the row in the data memory to access for the originator bit select address (bit select 3). It also determines (from the next six bits) the column in the data memory to access for the originator location address (address location 2). The output selector accesses the data bit at the intersection of these two addresses in the data memory as the output in time slot 62 to the switch DEMUX 1.

The output selector repeats this scanning and processing for all 64-column locations of the command memory. The switch DEMUX decombines the 64-channel bit stream into 64-individual data channels. It then sends the (originator) data bit in time slot 62 to subscriber 63. This is how subscriber 63 (the recipient) listens to subscriber 131 (the originator).

Analog call processing.

From the moment a subscriber goes off-hook (to start a call) until the last connected subscriber goes on-hook (hangs up), the switch takes a number of call processing actions. The following paragraphs and figures depict the most common analog processing actions. These actions involve calls originated from TA-341 type subscribers. We will describe three types of calls: nonsecure calls, analog-to-digital subscriber calls, and conference calls. Table 4-2 summarizes the seven switch processing actions common to most analog calls. Figure 4-5 depicts each of these actions.

Calls from analog subscribers (connected to the SDSG) to digital subscribers that terminate at the TDSG pass through the SDMX to the IMUs. (See Figure 4-6.) An IMU has the characteristics of an analog-to-digital converter. The digital output of the IMU exits the SDSG through the SDSG patch panel. From there, it passes to the TDSG for further processing. The following is the sequence of processing actions for completing a conference call. (See also Figure 4-7.)

Goes off-hook. The originator goes off-hook, receives DIAL tone, indicates precedence (if desired), and then keys C to request a conference call. The processor checks the originator's classmark for conference privilege. If not classmarked for conferencing, the originator receives ERROR tone.

Returns to originator. If all conference bridge units are busy, a BUSY tone returns to the originator. If a conference bridge is available, the originator again receives the DIAL tone.

Keys the directory number. The originator keys the directory number of the first party.

Connects call party. The called party is connected through the SDMX to the conference bridge unit and receives all signaling and information tones through the conference bridge.

Receives an answer. Once the caller receives an answer, he can add other conferees to the call. To do this, he keys C, receives a DIAL tone, and proceeds as stated in the two previous subparagraphs.

Digital call processing.

The full range of circuit switch services and switching functions is available to all digital subscribers (DNVT and DSVT subsets). Most of these are also available to those analog subscribers (TA-341 or signaling-compatible equivalent subsets) who are connected to the switch TDMX. Most of the major control operations involved in providing these services relate to the supervision, information or address signaling, and the matrix connections of each call. The text below describes the call processing sequence. It uses a DSVT subset as an example.

Request for service. This sequence begins when a subscriber on a loop places a call. The digital scanner, which sequentially samples each incoming line, detects the demodulated SEIZE code word and notifies the processor that it has found a service request (seize signal) on the caller's loop. The processor, after determining the type of subset that the caller is using, connects the proper LKG unit and digital receiver to the calling subscriber. This sets up the subscriber dial phase. Now the processor connects the digital signal generator to the subscriber and sends the DIAL code word and digitized DIAL tone signals. This tells the subscriber to begin dialing.

Dialing phase. The calling subscriber, upon hearing the DIAL tone, starts to key in the digits of the called party's number. This includes any applicable precedence digits and access codes. A connected digital receiver detects the digits at the switch. It then forwards them to the processor. Receipt of the first digit causes the IDLE code word to replace the DIAL tone. This code word is a product of the digital signal generator. Upon receipt of the last digit, the switch sends a signal to the DSVT from the digital signal generator. This asks what the mode (voice or data) of the subscriber is if the subscriber is classmarked as dual mode. The digital receiver detects the response to this signal, indicating a voice or data mode. The processor then disconnects the digital receiver and returns it to the pool. If the called party is busy, the digital signal generator sends a BUSY tone to the caller. If the called party is incompatible with respect to mode, voice, or data, the caller receives an ERROR tone.

Ringing phase. If the called party is on-hook and compatible, the switch connects a compatible LKG unit to the called DSVT's diphase loop modem. The digital signal generator then sends a RING VOICE or RING DATA code word. The called DSVT responds to a RING by activating its ringer and sending a ring acknowledge signal back to the switch. The called DSVT responds to a RING DATA signal by going electrically off-hook and sending a RING TRIP code word back to the switch. The switch digital scanner detects RING ACKNOWLEDGE or RING TRIP. The switch digital signal generator then responds by sending the calling party a RINGBACK SECURE, RING-BACK NONSECURE, or GO TO SYNC code word. Which one depends on the encryption mode of the call? The calling DSVT responds to these code words by starting up its internal ringback tone generator and sending the LOCK-IN code word to the switch. The switch detects the LOCK-IN code word with its digital scanner. It responds by sending the IDLE code word to the calling DSVT from its digital signal generator.

Ring answer phase. When the called DSVT goes off-hook, it sends a RING TRIP code word to the switch. The switch digital scanner detects RING TRIP, and the switch digital signal generator responds by sending back a RINGBACK SECURE, RINGBACK NONSECURE, or GO TO SYNC code word. Which one depends on the encryption mode of the call? The called DSVT responds to this code word by sending the LOCK-IN code word to the switch. The switch responds to LOCK-IN by proceeding to the traffic phase of signaling.

Traffic phase. When the switch has detected LOCK-IN from both the calling and called parties, it completes a connection between the calling and called parties diphase loop modems (end-to-end connections). Under paragraph 4-2, the subparagraphs on digital switchings and TDMX operation describe how the connection between calling and called parties is made. Additional code word exchanges will take place between the two DSVTs, but the switch processor ignores all but those involving RELEASE and C key.

Digital/analog calls. For calls between digital (DSVT and DNVT) and analog telephones, the switch must provide the type of code word signaling that takes place between two digital telephones in a normal digital-to-digital connection. This means that the switch detects LOCK-IN with its digital scanner and sends LOCK-IN to the digital telephone from the digital signal generator. The digital telephone responds to LOCK-IN by stopping its internal ringback tone generator (if activated) and sending the TALK ENABLE code word to the switch. When the switch detects a TALK ENABLE code word with its digital scanner, it responds by sending TALK ENABLE code word from its digital signal generator to the digital telephone. These continue for a fixed period of time. After that time, the switch makes the connection between the diphase loop modem and the IMU. If the calling party is the digital telephone, the switch may provide a RINGBACK tone. This travels from the analog ringback bus through the IMU. If the calling party is analog, RINGBACK travels from the digital signal generator through the IMU to the analog calling party.

Conferencing. The switch provides digital subscribers with the conferencing (more than a two-party call) privilege by connecting them through IMUs to the analog conference bridge units. Signaling for such calls is the same as for digital/analog calls. (See processing action in the subparagraph above.)

Subscriber release. When a DSVT goes on-hook, it sends the RELEASE code word to the switch. The switch detects the RELEASE code word with its digital scanner. It responds by sending the ONES code word (by disconnecting the subscriber's diphase loop modem) to the DSVT. A DSVT sending a RELEASE code word will shut off its power on receipt of a ONES code word.

Call release. When the other subscriber connected to a DSVT subscriber releases first, the switch sends an IDLE code word to the DSVT from the digital signal generator. The DSVT subscriber, hearing silence, will go on-hook, and the DSVT will send the RELEASE code word to the switch. From this point, the switch follows the subscriber release procedure. (See the above subparagraph.) The switch can force digital telephones to go electrically on-hook and, therefore, to send RELEASE signals. It does this by sending CUE and FORCE CLEAR code words to the digital telephone.

4-3. Initialization Process

The initialization process includes all those actions taken by planners, control elements, and switch operators that lead to circuit connection, data entry, and system start-up. This phase of switch operation is very important because poor procedures or errors made at this point can delay operation of the entire network. The planner must have a thorough appreciation of the initialization process and the activities at the lower levels of operation. This is especially true of the control that is exercised at the CSCE and at the node. Paragraph 5-6 gives a more complete picture of the planning process and paragraph 5-5 explains the flow of documentation and orders for a circuit switching network. This paragraph is an introduction to the initialization portion of the planning process.

After network planning and configuration have been completed and the CE order has been issued, the communications units deploy to designated sites. The CE order specifies these sites and provides certain basic information needed to initialize the switches. This information is also used by the control facilities to setup operations. The planner issues the CE order (in the name of the commander) from the CSPE. For a corps network, this CSPE is located at corps headquarters or at the corps signal brigade operating location. For a theater network, the CSPE is at a theater headquarters or at the theater communications command operating location.

The CE order may include sets of worksheets needed for initialization of the network switches. All of the information developed so far by the planners and engineers is used to configure the network and is reflected on these worksheets. The order, with the worksheets, goes to the operating units and the CSCEs which add data to these worksheets according to their local responsibilities. The worksheets then go to the node where they may be completed by the switch supervisor who allocates switch resources. The switch data base is loaded at the switch by direct entry from the worksheets (on-line), or by making a data base tape for later loading (off-line). Copies of the worksheets are returned through the same chain so that each level has a record of what has occurred.

If the CSCE has automated facilities or can use the processor of an AN/TTC-39, the data base load tape can be made at the CSCE for each switch under its control. This may save time and can help assure accuracy of the database. In this case, some items of information would still be supplied at the switch. In addition, the worksheets should accompany the tape as documentation and as a backup. They also are used to return information to higher levels. The following steps are a general summary of initialization actions. Note that some can begin as soon as the switch has reached its site if that location is known before the CE order is received. (See paragraph 5-7 for displacement information and time factors.)

Cabling and connections.

This includes power cabling, intershelter cabling, and cabling to transmission media. Subscriber cabling can be started as soon as subscriber units are in place. Some can be connected according to an SOP if the CE order specified this. Internal switch connections are also made in accordance with the CE order.

Interconnection and patching.

All signaling and communication lines entering or leaving the shelter or any major piece of equipment appear on a patch panel. Under normal conditions, initialization requires minimal patching. The patching option, however, lets you isolate lines or equipment to identify and correct faults. It also lets you make temporary use of redundant circuits to bypass failed lines or components without changing the site data base or configuration. (See TM 11-5805-681-12 for details.)

Strapping options.

The CE order with its attached worksheets will define the settings for the strappable PCBs. These include modems, buffers, MUX/DEMUX units, remote transfer switches, and timing generators. Strapping worksheets may be prepared by planners and/or switch personnel. If worksheets are prepared by switch personnel, sufficient information by the planner must be provided to ensure correct strapping. Information pertaining to cable length must be obtained from cable installers. An important item is the switch operating rate. (See paragraph 3-2.) You will need to verify and set it to either 16 or 32 kbs. This will be a matter mainly of setting circuit card strapping. All digital loops terminated on a given switch must have the same rate as all trunks in a given group cluster. However, on certain designated TDM group terminations, a switch operating at 32 kbs can accommodate digital trunk groups with a basic trunk channel rate of 16 kbs. You must also check the time and space division group interface to verify that the appropriate circuit cards are correctly strapped for channel modularity, loop rate, operation mode, and cable length. (See paragraph 4-5 for specific strapping instructions.)

Power-on procedures.

The power initialization procedure involves setting main circuit breakers and switches, ECU controls, battery circuit breakers, and AC and DC controls. It also involves checking various power indicators. (See TM 11-5805-681-12-1.)

Processor start-up.

Refer to TM 11-5805-681-12-1 for start-up procedures.

Data entry.

If not previously entered, you are now ready to enter the current operating data for your unit's tactical operation. This involves data entry worksheets keyed to prompts generated by the on-line processor. Paragraph 4-6 describes the use of worksheets and the sequence of data entry.


You may conduct on-line diagnostic testing after start-up either before or during call processing. Either the system software or the operator should detect faults in the on-line system.

4-4. Numbering Plan

A numbering plan to identify users is basic to any telephone communications network. In a network employing automatic switching, the numbering plan is the vehicle for programming network switches to accept and complete calls. It is the basis on which automatic switches route calls through the network. Users, of course, need a numbering plan to identify the parties they want to call. The Army has established the TTNP to identify all subscribers in its telephone networks. The TTNP is described below:

Figure 4-8 shows a hypothetical network containing typical combinations of subnetworks that might use the AN/TTC-39. The NATO members have reached a standardization agreement to use a unique 3-digit national identification (NI) number 9YX (where Y = 0 or 1; X = 0 through 9) for the military forces of each member country. The NI code for US forces is 914, for Germany 904, for the United Kingdom 913, and so on. The NI code serves as the first 3 digits of a 13-digit telephone number for NATO intercountry calls.

The next level down uses a 3-digit area code similar to a commercial area code. This code takes the form MYX (where M = 2 through 8) (sometimes shown as RA (regional area)). The figure shows three such areas, each with its own code. An MYX area code can serve either geographic areas or such organizations as a division, a corps, or a larger command area. You also can partition each MYX area by any one of three methods. In the figure, MYX areas 1, 2 and 3 each illustrate one of these methods. MYX area 1 is called a primary switch location (PRSL) subnetwork, MYX area 2 is called an NNX subnetwork, and MYX area 3 is called a mixed subnetwork.

In the PRSL subnetwork, you can partition an MYX area into as many as 23 primary zones (PR) or areas (PR = 72 through 98, except 80, 81, 90, and 91; 99 is reserved for fixed directory dialing described below). Each PR can then contain up to 100 SLs. For routing, each switch in an MYX area must be able to store path selection information for as many as 23 primary areas plus up to 100 switch locations for its own home primary area. Thus, the total storage for each switch is 23 + 100 or 123 items. It is not 23 x 100.

The AN/TTC-39 is capable of processing PRs of 22 through 98 (except 30, 31, 40, 41, 50, 51, 60, 61, 70, 71, 80, 81, 90, and 91), making a total of 63 PRs that can be assigned. The total number of SLs for each switch is 100. Thus, the total data storage of PRSLs for each AN/TTC-39 switch is 163. However, due to limitations of other equipments in the field with which the AN/TTC-39 must interact (for example, the AN/TTC-38), PRs for the present tactical numbering system are limited to 72 through 99, allowing only 123 PRSLs.

In an NNX subnetwork, you can partition an MYX area into as many as 640 switching center (NNX) codes (N (8 digits) x N (8 digits) x X (10 digits) = NNX (640 digits); N = 2 through 9). In a mixed subnetwork (MYX area 3), both PRSL and NNX subnetworks coexist within a single MYX area. As a network planner, your task is to set up a combination of MYX areas and NNX and PRSL subnetworks that serve their users well. This means that you must design an unambiguous numbering plan. Within each given MYX area, each primary area and each NNX code must be unique. If the MYX area contains mixed subnetworks, there must be no NNX codes in which the NN portion is the same as a primary area code. In the same way, within each primary area, each SL code must be unique.

The numbering plan for the AN/TTC-39 may use as many as 13 digits (for international calls) or as few as 3 digits (for abbreviated dialing). The 13-digit number takes the form:


The first 6 digits, 9YX-MYX, represent the NI and the area codes. They are for calls between different national boundaries and between different areas. Within a given MYX area, there can be no ambiguity in the assignment of the last 7 digits of the basic address. Similarly, the assignment of MYX area codes must be unambiguous in a given network. The AN/TTC-39 is fully compatible and can interoperate with any portion of a network that conforms to the basic 13-digit numbering plan outlined above.

The last 7 digits, NNXXXXX, of the basic address are like commercial telephone numbers. Such numbers use the first 3 digits to designate the exchange and the last 4 to designate the subscriber. However, in a tactical system, the AN/TTC-39 will use the current TTNP. This uses a 4-digit code, as if it were the commercial 3-digit exchange code, to identify the primary zone and switch location. It uses the last 3 digits to identify the subscriber. This 7-digit TTNP number takes the form:


The last 3 digits, XXX, identify the individual subscriber. These are further categorized into OXX numbers from 000 through 099, and GXX numbers 100 through 899. OXX numbers are reserved for identifying DC trunks that require operator assistance to complete the call. They are not assignable numbers. GXX numbers (G = 1 through 8) are divided into two groups for the use of the network planner:

  • IXX 100 through 699 (I = 1 through 6) identify individual subscribers and are the most common. Any IXX subscriber can dial any other IXX subscriber on the same switch without dialing a PRSL.
  • JXX 700 through 999(J = 7 through 9) usually identify units or activities served by a small manual switch having fewer than 100 lines.

You may wish to reserve certain numbers in specific positions of the basic PRSL-XXX format. This serves two purposes. First, it enables the switch to make certain decisions automatically. (See the paragraph below on abbreviated dialing.) Second, it gives the user some picture of the types of subscribers in the system. For example, you can use the IXX plan to identify subscribers by type of function. Do this by giving subscribers with the same job, regardless of echelon, the same last digit or last two digits. The first digit identifies the function. The number of the G1 could be 101 and the number of the G2 could be 202. Figure 4-9 illustrates a matrix that you can use to assign the second and third digits for subscribers of small switches. (For more information on this, see FM 24-26.)

In a nontactical network, the AN/TTC-39 can use a numbering plan much like the AUTOVON plan. This consists of a 3-digit switch code and a 4-digit subscriber code. It is essentially the same as the 7-digit commercial telephone numbering sys-tem. The nontactical number has the form:


The NNX-XXXX format is known as the 3/4 code and the PRSL-XXX format as the 4/3 code. The AN/TTC-39 can handle either the 3/4 or the 4/3 codes but can never use both at once. However, an AN/TTC-39 programmed to use the 3/4 code can function in a network with other switches that use the 4/3 code.

Abbreviated dialing.

Subscribers of the same switch may use abbreviated dialing. Switches using 4/3 numbering have automatic abbreviated dialing capability. For switches using 3/4 number plan, abbreviated dialing is optional and must be programmed on the ASI worksheet. This means that a user need dial only the last 3 or 4 digits of the basic 7-digit number:

GXX (for a PRSL-GXX format) or

GXXX (for an NNX-GXXX format).

G identifies up to 8 (G = 1 through 8) interconnected switches. The 3- or 4-digit format reflects the programming of the local switch (3/4 or a 4/3 code). A 3-digit (GXX) number would limit abbreviated dialing to a single local switch.

When a switch provides for abbreviated dialing, users must always dial the digit 9 to make regular calls outside of their local switch. Thus, the digit 9 (the escape code) must precede the basic 7- or 10-digit number, NYX-NNXXXXX. Expanded switch nodes (nodes composed of two to four AN/TTC-39 switches trunked together to form 1,200-to 2,400-line capacity switches) expand the abbreviated dialing service. Here one can dial 4 digits to place calls between the switches of the expanded node. The first digit of the GXXX abbreviated dial number format accesses a specific AN/TTC-39 within the node. The last 3 digits (XXX) access the subscriber.

Fixed directory dialing.

A key goal of any tactical network is to provide efficient telephone service to roving subscribers on the battlefield. This requirement has led to the fixed directory capability. In an AN/TTC-39 net-work, this feature enables roving subscribers to have fixed directory numbers, regardless of their locations. The fixed directory scheme has two elements:

  • The fixed directory subscriber list (FDSL).
  • The fixed directory unit list (FDUL).

The FDSL serves individual subscribers, who will have IXX or JXX numbers. FDUL serves selected units that may move frequently.

Fixed directory numbers are accessed by dialing the access code 99 (instead of a PR number) and then a 5-digit directory number. The 5-digit code has two forms:


(P and J = 7-9, X = 0-9, Z = 0-3, and I = 1-6.)

The switch first recognizes the 99 as indicating a fixed directory number. It then reads the 3-digit of the 5-digit number to identify the directory to which the number belongs (for example, J = the FDSL or I = the FDUL).

FDSL: Next, the switch reads the last 5 digits and consults the FDSL table for translation. It would, for example, translate PXJXZ into a PRSL-XXX number. The maximum number for these is 3,400. The network planner at the CSPE, in coordination with the CSCEs, assigns and controls the FDSL assignments. Once the FDSL is assigned, the FDSL directory can be published and service activated. The AN/TTC-39 will automatically accept FDSL numbers and will route all FDSL calls. The CSCE must determine and coordinate routing changes dictated by subscribers' movements.

FDUL: After reading the third digit of the 5-digit number (XXIXX) as an I, the switch reads the first 2 digits. It then consults the FDUL table for the translation. Each entry is of the form XX = PRSL. Since XX can equal 00-99, there are 100 (PRSL) entries in the FDUL table. The switch then adds the last three digits, IXX, to form the address: XXIXX = PRSL-IXX. As the unit moves, the network managers and controllers must update the FDUL table in some or all of the switches. Note that one update of the XX = PRSL table will identify hundreds of subscribers because XXIXX = PRSL-IXX.

Commercial network access.

A commercial network access capability is provided for the AN/TTC-39 subscriber. The commercial network access code is 5C. The dialing sequence for calls into a commercial communication system consists of P (for precedence routing through the tactical network only), then 5C followed by a second dial tone (from the commercial switch), then the desired commercial number. Dialing of the C key at the end of the commercial number indicates the end of dialing. Only one commercial network can be automatically accessed by the tactical subscribers within a given area code.

The actual number of digits in the address depends on the commercial network and the extent of service the planner desires. If the local commercial network uses a 7-digit number, the address for commercial access is:


Digital transmission required.

This request can be dialed via the prefix 7C from a local or long loop KY-68 or TA-954 terminal of an AN/TTC-39. The switching system will complete such calls by using only digital trunks between the originating and terminating digital switches. The call will not be completed if an appropriate digital path cannot be found. The quality of the signal is retained end-to-end because this service avoids the use of analog/digital conversions within the hybrid trunking network. The availability of the digital path allows the subscriber, after verbal coordination, to transmit digital data or digital facsimile as well. The basic form of the address for digital transmission required is:


Security required.

This request is transmitted to the AN/TTC-39 by dialing the prefix 1C from a local or long loop KY-68. The call will only be completed via a digital path to a KY-68 or an AN/TYC-39 message switch (MS), or to a protected distribution system for an analog or DNVT subscriber terminal. When used for the MS, this allows full-duplex transfer of data between an AN/TYC-39 and a secure digital net radio interface station (KY-90). The basic form of the address for security required is:


Analog transmission required.

The prefix 3C can only be used by analog terminals of an AN/TTC-39. The prefix ensures the calling subscriber an analog end-to-end connection. This may be used when transmission of quasi-analog signals is intended and where any degradation caused by employment of analog-to-digital conversions should be avoided. The basic form of the address for analog transmission required is:


End-to-end encryption required.

The prefix 4C can be used by local and long loop KY-68 subscribers to ensure setup of a digital, end-to-end, encrypted path to the called party. This service provides for a change from the voice to the data mode or for the use of a compartmented key by both subscribers after initial contact over the end-to-end encrypted link has been established. The basic form of the address for end-to-end encryption is:


Summary of numbering plans and dialing sequences.

Table 4-3 summarizes the fundamental properties of the TTNP. Subscribers using the AN/TTC-39 have available to them a variety of special service features based on their classmarks. The following numbering prefixes activate these special features:

P F E followed by 3- to 13-address digits.

P is a precedence code, F a special feature code, and E an escape code. When all three codes are used, they must be in the sequence shown. However, any or all of them in any combination may be omitted. If the precedence code is not dialed, the switch assumes routine precedence. In the absence of a special feature code, F, the switch treats the call as an ordinary voice call. Treatment then depends on the subscriber's classmark. For example, the switch treats a call from a secure voice subscriber as a secure voice call even though a special feature has not been indicated.

Dialing of the escape code, E, is not optional. When required to make an outside call (as in the 4/3 code when abbreviated dialing is available), it must be dialed. Otherwise (as in the 3/4 code without abbreviated dialing), it must not be used. Failure to use the E digit properly will generally cause the switch to receive an incorrect number of digits. This in turn will result in the return of an error signal to the calling party.

Subscriber dialing sequences. The different subscriber instruments with which the AN/TTC-39 must interface use specific codes to request special features. Table 4-4 lists these codes. Table 4-5 shows the allowable sequences that a subscriber may dial. The switch can accept all these sequences, but it rejects any sequence not listed and returns an error signal to the subscriber. Table 4-5 is divided into 11 categories, A through K. Each of these provides a set of compatible sequences. As an example, consider category D, special features with precedence. A subscriber may dial any of the precedence codes indicated, followed by a special feature code, followed by any of the six combinations of escape code and address digits. All sequences shown in the table are legal. However, the switch must determine from classmark data whether a particular subscriber can have a certain special feature. Remember that the escape code is not optional. Below are specific examples of allowable dial sequences in category D.




Analog required call at IMMEDIATE precedence to subscriber at a distant switch; local originating switch has abbreviated dialing requiring the escape code 9 for outside calls.


Call at PRIORITY precedence to local subscribe local switch has 3-digit abbreviated dialing.

Trunk dialing sequences. The AN/TTC-39 interfaces with a variety of trunk types. These in turn use a number of methods to indicate precedence and special features. Table 4-6 shows the particular legal sequences with which the switch is compatible. These sequences fall into 13 categories (A through M in the table). Any sequence not indicated is illegal and the switch will reject it.

4-5. Technical Management

Technical management involves the work done to prepare the switch for operation. This work implements planning done by a planner at a higher echelon. It consists of gathering all the required data and of fitting it into a format that enables the switch to be configured and the data entries to be made.

For the circuit switch, the basic management tools are worksheets. Worksheets are used in the planning process, in configuration, and in data entry. They can also function as scratch notes, as guides for initialization and operation, and as documentation for actions and orders. They are very important as guides because they encourage a system of orderly and logical thought and action. They are even more important as documentation because they help build a data base. Afterwards, they become an important record of that database for reference and emergency use. In addition, worksheets sent out with orders can transmit technical details in a common format. When returned, they become completion reports for the planner's file.

There are four types of worksheets: planning worksheets, configuration or strapping worksheets, data entry worksheets, and COMSEC management worksheets. Planning worksheets evolve from the actions at the planning level. Configuration or strapping worksheets are used to develop and record the information needed to make connections on circuit cards. These connections, or straps, change the configuration of the switch. Data entry worksheets provide a way to gather data. They also guide the making of entries for initialization or for data base changes. COMSEC management worksheets are used to configure COMSEC devices and to provide data for the data entry worksheets. (See FM 24-27A for further information.) When all of the worksheets are completed, it may be necessary to return to the planning worksheets to make  adjustments. These in turn may lead to adjustments on the configuration and data entry worksheets. The fact is that each part of the process is tied closely to the other parts.

Note that all worksheets described in the following subparagraphs are not required for every communications system development. Also, the planner may complete only a portion of those worksheets that are required. For example, the planner may be faced with developing a complete network from scratch, or with setting up only a subnetwork to interoperate with an existing network. In all cases, the planner will be responsible for initiating the preparation of various planning and data base worksheets. Such worksheets will then be completed with site-specific information prepared at the switch level. Reproducible forms are found in Appendix C. For further discussion of planner responsibilities and planning levels, see paragraph 5-6 and Figure 5-5.

Table 4-7 is a listing of all worksheets used for the circuit switch. The following paragraphs will describe each of these in turn. Use this table as a ready reference to the worksheets.

Planning worksheets.

The diagram in Figure 4-11 shows an example network of circuit switches. It illustrates the transition period during which digital equipment replaces older analog equipment. The planning to be done is for one of the AN/TTC-39 switches or nodes in this network. (See paragraph 5-6 for more information about developing networks. Also see Appendix B for an example of how the planning worksheets are used.)

DD Form 2490-1, Network Planning and Configuration Data--Subscriber List (Figure 4-10). To analyze what is needed at switch A (Figure 4-11), start with worksheet P-1 (P for planning) in Figure 4-10. List all the subscribers for the switch. An operations order or plan may already provide this information. If not, use available documents to create the list. Consider the switch capacity and, if necessary, assign priorities for service. If a directory number has not been assigned, make the assignment from available numbers. Assign equipment according to availability. The rest of the information on the worksheet is for assigning class of service marks (classmarks) during the data entry process. Use the AFD worksheet (D-19) to make fixed directory assignments. To make essential user bypass (EUB) assignments, use the AEU worksheet (D-7). For everything else, use the ATS worksheet (D-3). Paragraph 3-7 explains each of these classmarks.

DD Form 2490-2, Network Planning and Configuration Data--Trunk Group Cluster List (Figure 4-12). This worksheet is for gathering the information needed to determine the requirements for trunking between switches. Because the AN/TTC-39 is a hybrid switch (analog and digital capabilities), the interswitch trunking is composed of sets of trunks with various transmission characteristics. If the trunks had identical characteristics, they would form a trunk group. But these are varying, and so they are called trunk group clusters. In the example network in Figure 4-11, the numbers on the lines around switch A represent TGCs. List each of the trunks in each of the TGCs on worksheet P-2. If TGCs have not yet been assigned, this worksheet can be used to develop the trunk composition of each.

List each TGC number and the DTG number of the digital trunks. Under channels list the number of channels assigned both to traffic and to signaling. The destination switch is also listed by NYX-NNXX number. Equipment at both ends is listed to help determine the technical characteristics in worksheet P-4. The traffic limits columns are to indicate whether outgoing calls for each trunk are to be restricted by precedence. For this worksheet check the highest level of precedence for each trunk. Later on, the data entries will total these to classmark each TGC. (See ATG worksheet.) If there is to be no restriction on precedence, leave blank. Mark yes or no for glare, spill forward, and to show if this is part of a TGC to an access node. Finally, you can assign the circuit number now or later on when filling out the ATS worksheets.

DD Form 2490-3, Network Planning and Configuration Data--Loop Terminations (Figure 4-13). Figure 4-13 shows worksheet P-3 which details the technical information needed to terminate a subscriber loop. This information is the basis for equipment assignment and switch configuration. Worksheet P-3 must be prepared in conjunction with P-1. Under technical characteristics, indicate 2-wire or 4-wire (2W/4W) and supervision AC or DC for both analog and digital loops. Indicate common battery or local battery (battery) and signaling characteristics (signaling) for analog loops. These can be 20-Hz ringdown, 1600-Hz ringdown, 2600-Hz SF, DC closure, or one-way automatic/one-way ringdown.

You can now assign a modem or LTU. (See worksheet P-5 for available equipment.) If an adapter is needed for an analog termination, list it here and assign the location and type. Be cautious when adapters are used because all loops with adapters must enter the SEP through jack J1. (J1 is wired to the CEG special circuits patch panel and, in turn, to the SDSG patch panel.) Thus, you must select locations for circuit cards used for LTU and adapter combinations from those slots hardwired to J1.

DD Form 2490-4, Network Planning and Configuration Data--Trunk Terminations (Figure 4-14). Figure 4-14 shows worksheet P-4. It is similar to the loop termination worksheet (P-3). For clarity P-4 repeats some of the information in the trunk list. Both worksheets provide information used to assign and to configure the switch.

List both analog and digital trunks by trunk and TGC. Destination equipment identifies the destination switch or other equipment. Enter the type of TGC (interswitch, commercial, private automatic branch exchange DIBTS) and the signaling characteristics (1600-Hz ringdown and 2600-Hz SF dial). Assign the modem of LTU to be used, and determine the SDSG or TDSG assignment.

Now select and enter the trunk rates. The number of channels refers to the number of multiplex data stream channels (8, 9, 16, 18, 32, 36, 48, 64, 72, 128, or 144). Both the diphase group modem and the DISGM require selection of cable length. Cable for the DISGM cannot exceed 1/2 mile, but the diphase group modem can use cable of up to one mile. For nine channel multiplexer/demultiplexer list the nine channel MUX/DEMUX cards to be used and their locations. For TSB and adapters, list the equipment.

DD Form 2490-5, Network Planning and Configuration Data--Circuit Card Inventory (Figure 4-15). Figure 4-15 shows worksheet P-5. It is both an inventory list and a master checklist of all circuit cards in the switch. This includes the adjustable or strappable cards described in the next paragraph. This worksheet is important because there are a number of cards and a number of ways in which they can be used.

Specifically, the switch employs over 150 circuit cards, also called printed circuit boards or PCBs. For example, an LTU is a circuit card. There are various ways of connecting these to make a particular switch configuration. These configurations will depend on the size of the switch, its type (paragraph 2-2), what it has been assigned to do, and the number and kinds of cards that are used for spares or are being repaired. The circuit card inventory keeps track of these cards and shows where and how they are being used.

One of your early actions when activating a switch should be to make a complete inventory of all circuit cards installed and in spare racks. This will show what the configuration is and show the capability of the switch. You can fill out worksheet P-5 either by card type alphabetically or by card number. Location shows the card nest or other location. Entries under SDSG/TDSG/CEG and number of cards will help identify the location. The strapped column provides a cross reference to the strapping worksheets. On this worksheet, the column is either a record that strapping has been done or a reminder that it needs to be done. The three last columns are for counting. When cards are to be assigned as the requirements change, you can use the card count column as a running tally of the number available. For example, if five cards are available, the column might read: as the first three cards are used or assigned.

Tables A-3 and A-4 will help you use worksheet P-5. Because these tables list all the matrix addresses, you can use them to record card assignments and to check available resources. If you use these tables as worksheets, label them P-5A and P-5B.

Strapping worksheets.

Of the approximately 150 circuit cards in each switch, 22 types must be strapped manually. This strapping adjusts the loop rate, trunk rate, clock rates, polarity, frequency responses, and other unique functions as described in the following paragraphs. Paragraph 3-2 gives an example. In that example, a series of 11 cards is strapped to assign the switch loop rate to either 16 or 32 kbs.

Of the nine worksheets (Figures 4-16 through 4-24) used for strapping, three of them consolidate several cards on one page. For ease of reference, the card identification is the mnemonic and is listed to the left at the beginning of each worksheet. These are numbered S-1 through S-9 (S for strapping). In several instances, the strapping tables use the term frequency. This refers to the baseband information transmission rate of a DTG. (See paragraph 3-2 for further explanation.) It is not necessary to know this rate for strapping because the decision will depend on the number of channels selected and on the loop rate of the switch. However, it is useful to know this baseband rate (expressed in kbs, robs, and sometimes in Hz). It enables you to check the information you are gathering against the tables and with the data in TM 11-5805-681-12. Table 4-8 shows the fixed relationships between channel modularity, switch loop rate, and the DTG baseband rates.

DD Form 2490-6, Network Planning and Configuration Data--Matrix Strapping (Figure 4-16). There are nine card groups shown on this form. They are identified and explained as follows:

COMSEC transmit controller (COMXC) (worksheet S-1) (Figure 4-16). The COMSEC controller links the COMSEC equipment with the CPG. There are two controllers in the CEG, each of which consists of four cards. One card in each is the transmit controller. It is strapped to show the size of the switch, 300 lines or 600 lines. Strap both cards because enable signals from the CAP/CEM select the controller. Make the following worksheet entries:

Card number. Enter A and B, as listed.

Switch configuration. Enter 300-line or 600-line.

Straps. For 600-line: J2-J3.
            For 300-line: J4-J3.

Processor control unit 6 (CTLU 6) (worksheet S-1) (Figure 4-16). There is a CTLU 6 for each of the two processors. Both CTLU 6s are strapped to connect either COMSEC controller (A or B) to the associated processor. Normal connection is A connect and B disconnect. The cards reside in the CAP/CTL nest. You must strap them both to show connection or disconnection. The straps are operational only when the CAP/CTL panel is in the manual mode. Make the following worksheet entries:

Card number. Enter A and B, as listed.

Status. Enter connect or disconnect. Normal is A connect, B disconnect.

Straps. For connect: J2-J3.
            For disconnect: J3-J4.

Control and alarm panel/TTY buffer band rate (CAP 09) (worksheet S-1) (Figure 4-16).

This card provides the interface between the TTY and the switch electronics. One strap selects the baud rate or speed at which the TTY operates. Usual operation is at 300 baud. Make sure the teletype is set for the same rate. Make the following worksheet entries:

Baud rate. Enter 300 for an interface rate of 300 baud, or enter 150 for an interface rate of 150 baud.

Straps. For 300: J3-J4.
            For 150: J2-J3.

Call service position modem (CSPMD) (worksheet S-1) (Figure 4-16). This card is one of five in a card nest within the CSP console. It provides part of the interface between the CSP and the TDSG loop modem and the SDSG line termination unit. Two straps select the loop rate and the function. Strap the cards according to the CSPs used. Make the following worksheet entries:

Call service position. Enter L for the local CSP and R1, R2, or R3 for remote positions, as listed.

Function. Enter Normal or Loopback. The latter is for maintenance only.

Loop rate. Enter 32 kbs or 16 kbs.

Straps. For 32 kbs Normal: J6-J7 and J3-J4.
            For 16 kbs Normal: J5-J6 and J3-J4.
            For 32 kbs Loopback: J6-J7 and J2-J3.
            For 16 kbs Loopback: J5-J6 and J2-J3.

Matrix receive controller (MXRCA) (worksheet S-1) (Figure 4-16). The matrix controller interfaces the central processing unit controller with the space division matrices and the time division matrices. In each of the two matrix controllers there are transmit and receive sections. The MXRCA is one of three cards in the receive section. It is strapped to show the loop rate. Strap both cards because the CPU central controller selects the controller. Make the following worksheet entries:

Matrix controller number. Enter A and B, as listed.

Loop rate. Enter 32 kbs or 16 kbs.

Straps. For 32 kbs: J4-J3.
            For 16 kbs: J2-J3.

Local timing generator (LTG) (worksheet S-1) (Figure 4-16). The LTG is part of the switch timing circuits which provide all clock signals for operation. There are three LTGs that use the output of the MTG and that deliver timing frequencies to the TDSG and SDSG. Strapping selects the loop rate. Strap all three cards. Make the following worksheet entries:

LTG number. Enter 1, 2, and 3 as listed.

Loop rate. Enter 32 kbs or 16 kbs.

Straps. For 32 kbs: J2-J3.
            For 16 kbs: J3-J4.

Matrix interface G (MTX-G) (worksheet S-1) (Figure 4-16). There are matrix interface units in each SDSG. These assist in signal routing and switching in the space division matrix. The MTX-G has a strap that identifies the group of unite with one of the SDSGs. Make the following worksheet entries:

SDSG number. Enter 1-4, according to the number used, as listed.

Card number. Enter 1-4 to indicate the number of cards to be strapped.

Straps. For SDSG 1: J7-J6.
            For SDSG 2: J5-J6.
            For SDSG 3: J4-J3.
            For SDSG 4: J2-J3.

Remote signaling buffer controller multiplexer/demultiplexer (RSBMD) (worksheet S-1) (Figure 4-16). This device is the interface between signaling buffers and the central processing group. It transfers input and output data and provides the needed multiplexing and demultiplexing. There are four cards for each TDSG, two of which are spares. Strapping identifies which cards are used and shows input and output units. Make the following worksheet entries:

TDSG number. Enter 1 and 2, as listed, according to the number of TDSGs.

Card number. Enter 1 through 4 for each TDSG to show which two cards are used.

Straps. For TDSG 1, Input is: J5-J6. Output is: J4-J3.
            For TDSG 2, Input is: J7-J6. Output is: J2-J3.

Digital scanner B (DSCNB) (worksheet S-1) (Figure 4-16). The digital scanner provides status monitoring of all TDMX switched lines and trunks. It also updates the processor memory when a change occurs. There are two cards for this scanner, but only card B needs strapping. There is a scanner for each TDSG in use. Make the following worksheet entries:

TDSG number. Enter 1 and 2 to indicate the number of TDSGs used.

Straps. For TDSG number 1: J11-J12, J9-J8, J5-J4.
            For TDSG number 2: J13-J12, J7-J8, J5-J4.
            For spare: J11-J10, J7-J6, J3-J2.

DD Form 2490-7, Network Planning and Configuration Data--Modem/Clock Strapping (Figure 4-17). There are three card groups shown on this form. They are identified and explained as follows:

Group buffer (GRPBF) (worksheet S-2) (Figure 4-17). The GRPBF is part of the transmission group module. The transmission group module works with the trunk encryption device to provide timing adjustment and synchronization. There are four GRPBF cards per TDSG. Strap all four. Make the following worksheet entries:

TDSG number. Enter 1 and 2, as listed, to show how many TDSGs are used.

Card number. Enter 1-4 for each.

Loop rate. Enter 32 or 16 kbs.

Number of channels. Enter 8, 9, 16, 18, 32, 36, 48, 64, 72, 128, or 144.

Channel straps. Connections are as listed in Table 4-9.

Loop rate straps. For 32 kbs: J16-J15.
                            For 16 kbs: J14-J15.

Equipment option. Enter TGM and TDMX combination loop rates.

Equipment option straps. Both 32 kbs: J17-J18.
                                          TGM 16, TDMX 32 kbs:
                                          Both 16 kbs: J17-J18.

Diphase supergroup modem (DISGM) (worksheet S-2) (Figure 4-17). The DISGM terminates digital transmission groups in the same way as the diphase group modem but with greater channel capacity. The modem uses only two sets of straps. These specify the cable length and the bit rate, the selector rate, and the low pass band frequency. There are up to four modems per TDSG. Strap all that are used. Make the following worksheet entries:

TDSG number. Enter 1 and/or 2 for TDSG, as listed.

Modem number. Enter 1-4 for modem or card identification for each TDSG.

Cable length. Enter 0, 1/4, or 1/2 in miles, or enter loopback.

Cable length straps. For 0: J24-J25, J18-J19, J21-J22.
                              For 1/4: J24-J23, J18-J19, J21-J20.
                              For 1/2: J24-J25, J18-J17, J21-J20
                              For loopback: J24-J23, J18-J17, J21-J20.

Loop rate. Enter 16 or 32 kbs.

Channels. For 16 kbs, enter 128 or 144.
                 For 32 kbs, enter 64, 72, 128, or 144.

Straps. Connections are as listed in Table 4-10.

Group clock selector (GCLK) (worksheet S-2) (Figure 4-17). The GCLK is a part of the TDSG. It selects red or black clock (timing) for the group modems and the supergroup modems. This determines whether the modem operates on encrypted or nonencrypted groups. There are four cards per TDSG. Strap all four. Make the following worksheet entries:

TDSG number. Enter 1 and/or 2, as listed.

Card number. Enter 1-4 for each TDSG.

Loop rate. Enter 32 kbs or 16 kbs.

Loop rate strap. For 32 kbs: J50-J51.
                           For 16 kbs: J34-J35.

Clock. Enter red or black.

Clock straps. Make sixteen connections as in Table 4-11. Use two rows to enter the straps for each card.

DD Form 2490-8, Network Planning and Configuration Data--MUX/DEMUX Strapping (Figure 4-18). There are three card groups shown on this form. They are identified and explained as follows:

Nine channel multiplex/demultiplex (NCMD) (worksheet S-3) (Figure 4-18). Each TDSG has a group multiplexer/demultiplexer, which consists of up to 16 NCMD cards. Each of these cards combines nine 32-kHz digital data streams into a single data stream. These cards can themselves be combined to form one overall data stream. There are three groups of straps on each card. One selects the trunk rate, the second selects the frame rate (loop rate), and the third selects the input/output ports. The modularity noted in the table on the following page can be in multiples of either 8 or 9. The choice made will affect the multiplex operating frequencies but not the use of the channels available in the multiplexer. Note that all NCMDs in use are strapped the same. Thus, you will make one entry for each TDSG. Make the following worksheet entries:

TDSG number. Enter 1 and/or 2, as listed.

Card number. Use is optional.

Number of NCMDs. Enter 1, 2, 4, 6, 8, or 16 according to the number of channels needed.

Number of channels. Enter 8, 9, 16, 18, 32, 36, 48, 54, 64, 72, 128, or 144.

Channel straps. Make the connections as listed in Table 4-12 (Part 1).

Loop rate. Enter 32 kbs or 16 kbs.

Loop rate strap. For 32 kbs: J30-J31.
                           For 16 kbs: J29-J30.

Interface. This selection is the input/output port. (See Table 4-12 (Part 2).)

First card. The entry of yes or no shows which card is the first in the series. (See Table 4-12 (Part 2).)

Straps. Make the connections in Table 4-12 (Part 2)).

Dipulse group modem (DPLSM) (worksheet S-3) (Figure 4-18). This modem is used for data over transmission links that interface with current multichannel equipment such as TD-754, TD-204, AN/GRC-144, and AN/GRC-143. There are up to four modems per TDSG. Make the following worksheet entries:

TDSG number. Enter 1 and/or 2, as listed.

Modem number. Enter 1-4 for each, as listed.

Modulator cable length. Enter 1, 3/4, 1/2, 1/4, or 0 miles, or enter loopback.

Straps. Make connection in Table 4-13 (Part 1).

Demodulator cable length. Enter 1, 3/4, 1/2, 1/4, or 0 miles, or enter loopback.

Straps. Make connections in Table 4-13 (Part 2).

Loop rate. Enter 16 kbs or 32 kbs.

Number of channels. Enter 9, 18, 36, 72, or 144.

Information rate straps. Make connections in Table 4-13 (Part 3).

Repeater power. Enter ON or OFF.

Straps. For ON: J3-J4.
            For OFF: J2-J3.

Diphase group modem (DIGPM) (worksheet S-3) (Figure 4-18). These modems terminate DTGs. There are usually four modems per TDSG. Four groups of straps are used to set trunk rate, cable length, repeater power, and the low pass band on a single card. Make the following worksheet entries:

TDSG number. Enter 1 and/or 2, as listed.

Modem number. Enter 1-4 for each TDSG, as listed.

Cable length. Enter 0, 1/4, 1/2, 3/4, or 1 mile, or enter loopback.

Cable straps. For 0: J39-40, J33-J34, J36-J37.
                      For 1/4: J39-J38, J33-J34, J36-J37.
                      For 1/2: J39-J40, J33-J32, J36-J37.
                      For 3/4: J39-J38, J33-J34, J36-J35.
                      For 1: J39-J40, J33-J32, J36-J35.
                      For loopback: J39-J38, J33-J32, J36-J35.

Loop rate. Enter the loop rate at which the switch operates, 16 or 32.

Number of channels. Enter 8, 9, 16, 18, 32, 36, 48, 64, or 72 to show the number of channels multiplexed on the TDSG.

Channel straps. For channel options, use Table 4-14.

Low pass band selector straps. For 16-kbs loop rate and channels 8, 9, 16, 18, 32, and 36 and for 32-kbs loop rate and channels 8, 9, 16, and 18: J29-J30, J21-J22, J18-J19.

For 16 kbs and channel 64 or 72 and for 32 kbs and channel 32 or 36: J30-J31, J20-J21, J18-J19.

For 16 kbs and channels 96, 128, and 144 and for 32 kbs and channels 48, 64, and 72: J27-J28, J24-J25, J18-J19.

Repeater power ON/OFF. Enter ON or OFF.

Repeater power straps. For OFF: J2-J3. For ON: J3-J4.

DD Form 2490-9, Network Planning and Configuration Data--Normal Wideband LTU (Figure 4-19). For normal wideband line termination unit (NWLTU) use worksheet S-4. This LTU is one of six types that directly terminate a variety of analog subscribers. Each one provides for loop, trunk, or adapter line interface with the SDMX. The normal wideband LTU is strapped to supply either DC (common battery power) or AC (tone supervised). There are two LTUs per card and a maximum of 60 cards per SDSG. Make the following worksheet entries:

SDSG number. Enter 1-4.

Card number. Enter 1-60.

Supervision. Enter AC or DC.

Straps. Make the following connections:

            For DC or common battery power, NWLTU 1 (top) is: J7-J6 and J4-J3. NWLTU
            2 (bottom) is: J13-J12 and J10-J9.
            For AC, NWLTU 1 (top) is: J5-J6 and J2-J3. NWLTU 2 (bottom) is: J11-J12 and

DD Form 2490-10, Network Planning and Configuration Data--Type II Modem (Figure 4-20). For MOD 21-22 use worksheet S-5. Type II modems provide an interface for common channel signaling from the trunk signaling buffer with an analog out-of-band signaling channel. These modems provide a single channel, 4-wire, full-duplex, synchronous, frequency shift capability. There are two type II modems for each SDSG. Each modem consists of two cards which are labeled II-1 and II-2 (or MOD 21 and MOD 22). Both of the cards are strapped. Strapping is done with alignment adjustments as described in TM 11-5805-681-12. Make the following worksheet entries:

SDSG number. Enter 1-4.

Modem number. Enter 21 or 22.

MOD 21 interface. Enter MIL STD 188C (end-to-end encryption) or LKG.

MOD 21 interface strap. For 188C: J2-J3.
                                        For LKG: J3-J4.

MOD 21 equalizer. Enter In or Out for delay equalization. Normally it will be out.

MOD 21 equalizer strap. For In: J5-J6.
                                        For Out: J6-J7.

MOD 22 mode. Enter master or slave. Each circuit has a master and a slave. The controlling switch is the master.

MOD 22 mode strap. For master J2-J3.
                                   For slave: J3-J4.

MOD 22 baud rate. Enter 150, 300, 600, 1200, or 2400. Common channel signaling uses 1200 baud. 2400 baud requires baseband conversion to duobinary format. Others are frequency shift keying.

MOD 22 baud rate strap. For 150: J7-J8.
                                         For 300: J6-J7.
                                         For 600: J5-J6.
                                         For 1200: J9-J10.
                                         For 2400: J10-J11.

MOD 22 transmit data. Enter 1200 (normal) or 2400 (inverted) Hz to show the mark frequency. Note that receive data (see below) must have the opposite assignment.

MOD 22 transmit data strap. For 1200: J12-J13.
                                                For 2400: J13-J14.

MOD 22 transmit clock. Provide comparison with the transmit clock by selecting normal for trailing edge sampling of the transmitted signal, or invert for leading edge sampling. Use normal when selecting the master mode and invert when selecting a switch in the slave mode.

MOD 22 transmit clock strap. For normal: J15-J16.
                                                 For invert: J16-J17.

MOD 22 receive data. Enter 1200 or 2400 Hz to show the space frequency.

MOD 22 receive data strap. For 2400: J18-J19.
                                              For 1200: J19-J20.

MOD 22 receive clock. Provide comparison with the receive clock by selecting normal for leading edge data alignment, or invert for trailing edge data alignment. Use normal for the master mode and invert for the slave mode.

MOD 22 receive clock strap. For normal: J21-J22.
                                               For invert: J22-J23.

DD Form 2490-11, Network Planning and Configuration Data--Trunk Signaling Buffer B (Figure 4-21). For trunk signaling buffer B (TSBFB) use worksheet S-6. The TSB works with the signaling buffer controller to provide common channel signaling. It consists of two cards, A and B, of which the B card is a subchannel MUX/DEMUX and a type II modem interface. There are 14 TSBs for each TDSG. The B card is strapped to show interfaces, the mode, and the clock rate. Make the following worksheet entries:

TDSG number. Enter 1 or 2.

Interface. Enter type II modem or TDMX.

Bit rates. For TSB, switch, and trunk, enter 16 kbs or 32 kbs for each.

Straps. Make connections in Table 4-15.

DD Form 2490-12, Network Planning and Configuration Data--Switch Memory Control (Figure 4-22). For switch memory control (SWMCT) use worksheet S-7. This card identifies the TDMM that makeup a TDMX with the associated TDSG. Each TDSG uses three or more TDMMs. Each TDMM provides 64-channel terminations. Only two TDSGs are shown here. Make the following worksheet entries:

TDSG number. Enter 1 or 2.

TDMM number. Enter 1-6,13-15, or 18 or according to the number used.

Straps. Make connections in Table 4-16.

DD Form 2490-13, Network Planning and Configuration Data--Loop Clock Selector (Figure 4-23). For loop clock selector (LPCLK) use worksheet S-8. The LPCLK is a part of the TDSG. It selects red or black clock (timing) for the loop modems. This determines whether the modem handles encrypted signals (black) or nonencrypted signals (red). There are five cards per TDSG. Make the following worksheet entries:

TDSG number. Enter 1 or 2.

Card number. Enter 1-5.

Loop clock. Enter black or red.

Straps. Make connections in Table 4-17.

DD Form 2490-14, Network Planning and Configuration Data--Diphase Loop Modem A (Figure 4-24). For diphase loop modem A (DILPA) use worksheet S-9. This modem provides synchronous, 4-wire, full-duplex interface between digital subscribers and the time division switching equipment. It can provide remote power for digital terminals. Strapping on this card supplies-56 volts DC over a phantom loop to a DSVT or DNVT. Make the following worksheet entries:

TDSG number. Enter 1 or 2.

Card number. Enter the identification of the card.

Connect/disconnect -56 V. Enter connector disconnect.

Straps. For connect J2-J3.
            For disconnect: J3-J4.

4-6. Data Entry

The data base for the circuit switch consists of data lists or tables. These tables provide the processor with the information needed to route, to switch, and to perform the subscriber services described in paragraph 3-7. The information in the tables also shows the status of the switch at a particular time.

Entries and changes to the data base are via a keyboard and a VDU. A series of commands from the keyboard calls up various forms, or menus, on the VDU screen. The operator then makes keyboard entries corresponding to the information to be placed in the data base.

Each of the commands is a mnemonic group of letters that tells the switch to add, change, delete, or display the information. There are two major types of command: assign and display. The assign type includes add, change, and delete functions. It may also include a command to display the existing data. The display command is for displaying the data only. Table 4-18 is a list of these commands. For most of the assign commands, there are worksheets showing how to assemble the data. However, some commands deal with operator functions that do not need worksheets.

Data entry worksheets are important both to switch personnel and to planning personnel. At their locations, worksheets are records of planned and completed actions and show what the switch capabilities are. They are also important as guides for assembling information. Finally, they encourage a system of logical actions.

Validation and ramification.

To avoid errors, the switch checks each data entry. It also informs the operator of the results of certain entries. It performs validation checking on each entry to see if the entry is acceptable and if its size and range of values are correct. Ramification checking on each entry detects data base discrepancy errors and warns the operator of possible results of these errors and of the entries themselves. If an attempted action will change certain critical elements, or if there is an error that must be corrected, ramification message numbers will show on the screen. Each assign command produces a specific set of messages.

(Refer to TM 11-5805-681-12 for lists of ramification messages for each command.) These messages can also tell the operator when an action cannot be taken. They do this by displaying an F (for fatal), which blocks the entry. In such cases, it may be necessary to redo an entire sequence of data entries to produce the desired action.

Data entry process.

Figure 4-25 shows the process of data entry. For each step of the process, the figure lists the three-letter mnemonics of the worksheets used for entering data.

The first step defines the switch functions and enters them into the data base. ASI initializes the switch and ASC assigns the switch classmarks. This step also involves assigning the CSP portion of terminal types (ATT) and the switch supervisor portion of terminal services for loops (ATS A).

The next step assigns terminal services. This concludes the assignment of terminal types (ATT) and terminal services for loops (ATS). This step also involves configuration for the essential user bypass (AEU).

The third step sets up trunking. This involves assigning the digital transmission groups (ADT) and organizing the trunk group clusters (ATG). This step also involves assigning terminal services to trunk terminals (ATS).

You will make COMSEC assignments by assigning the location of data for the key distribution center (AVL) and, when needed, by rekeying COMSEC nets (ANR).

Routing constitutes the fifth step. It involves assigning commercial routing (ACN), NYX routing (ANY), alternate area routing (AAA), NN routing (APR), NNX routing (ANN), NNXX routing (ANX), XXX routing (AXX), and XX routing (ASL). Most of this work involves assigning trunk group clusters and their alternates to particular functions.

The final step (and the largest) is the assignment of subscriber services. This involves implementing the classmarking that was done for each terminal insteps 2 and 3 (ATS) by grouping classmarks and providing access to them. Products of this task include compressed dial lists (ACP and AIC), fixed directory lists (AFD), and conference lists (APC). Also included are such data controls as call inhibit (ACI), zone restriction (AZR), and digit editing (ADE). This step also involves assigning secondary traffic channels to a terminal (AST). Finally, it involves organizing the essential user bypass lists for other switches (ARB) and, when necessary, adjusting or activating them (AAR).

Data entry worksheets.

Tables 4-7 and 4-18 list the data entry worksheets and identify them as D-1 through D-30 (D for data). They are numbered by order of entry. (This greatly facilitates error checking, described in the subparagraph on validation and ramification, above.) The only exception involves the terminal services worksheet, D-3 (ATS). Entry of the trunk portion of worksheets B and C must follow the assignment of trunk group clusters, D-6 (ATG).

Before you use these worksheets, review paragraph 4-4 on numbering plans. The numbers used in the worksheets are coded according to the following system:

X = 0 - 9
N = 2 - 9
G = l - 8
Y = 0, l

P = 7 - 9
J = 7 - 9
Z = 0 - 3
I = 0 - 6

M = 2 - 8

A = l - 4
BB = 01 - 13
CC = 01 - 12

DD = 01 - 15
EE = 00 - 63

Under certain circumstances you will find number assignments already recorded for units or switch components. This could be the case if an SOP has been established to make switch configuration easier. If not, the number assignment will be sequential, and one of the planning worksheets will probably already have assigned it. If it is not there, you can make the assignment at the time you fill out the data entry worksheets.

DD Form 2490-15, Network Planning and Configuration Data--Switch Initialization and Classmark Worksheet (Figure 4-26). The assign switch initialization (ASI) and assign switch classmark (ASC) functions are necessary for the initial activation of the switch. Changes to ASI will cause major data base changes but changes to ASC can be made without a major update. Worksheets D-1 (ASI) and D-4 (ASC) are combined on one worksheet page for ease of entry.

Make the following worksheet entries for ASI:

SDSG matrix size. Enter 0-4 to show the number of space division switching groups (analog).

TDSG matrix size. Enter 1-4 to show the number of time division switching groups (digital).

NOTE: These two groups of numbers define the configuration of the switch. For example, 2/1 is the usual 300-line configuration and means two SDSGs and one TDSG.

Single shelter switch. Enter Y for YES or N for NO. This differentiates between the 300-line and 600-line switches.

Numbering plan. Enter 3/4 or 4/3 to show which numbering scheme is used. (See paragraph 4-4 for descriptions of these.) Usually 4/3 is used.

16/32-kbs switch. Enter 16 or 32 to show the operating rate at which the switch operates. Usually 32 kbs is used.

Time. These entries set the time at which the switch begins to operate. Under day (the Julian date) enter 1-366. Under hour enter 0-23. Under minute enter 0-59. Under tenths of minutes enter 0-9.

The following entries are for the 3/4 numbering plan only:

Abbreviated dial. Enter Y for YES or N for NO to indicate whether the switch will use abbreviated dialing. (See paragraph 3-7.)

Local subscriber code. Enter a local subscriber code in the format NNXG. NNX is the switch code, and G is the number all subscriber numbers will begin with.

Make the following worksheet entries for ASC:

Alternate routing. This entry enables the switch to perform alternate routing according to a routing plan. This applies only if the switch is operating in the tandem mode for a particular call. Enter Y for YES or N for NO.

Gateway classmark. This classmark is used to reduce analog-to-digital conversion in a network or in several networks. A NO entry (N) prevents conversion on alternate routes if the primary TGC is an interswitch TGC (from AN/TTC-39 to AN/TTC-39). A YES entry (Y) allows conversion.

NN code for TTC-30 trunks. If the switch connects to an AN/TTC-30 telephone switch, this classmark provides for numbering plan compatibility. If there is no such connection, leave blank.

Satellite link number. If the switch uses satellite links for trunking, this classmark adds a path delay to introduce external echo suppressors on 2-wire analog to 4-wire connections. The classmark allows you to set the maximum number of satellite links in a connection. Although four are possible, for tactical systems only one satellite link is permitted. Enter 1 or, if no satellite is used, enter 0.

NATO home area. If the switch homes on a NATO switch, this entry identifies that home area. Use 9YX; otherwise leave blank.

Switch supervisor loop digits. Use GXX or GXXX to identify the directory number assigned to the switch supervisor.

SSB reset. Enter N for NO in all cases because the switch does not use the SYSCON signaling buffer (SSB).*

Tactical communications control facility (TCCF) intercept. Enter N for NO in all cases.*

TCCF element. This entry involves the use of multiple automatic control elements. Always leave blank.*

TCCF Auto. This entry also involves automatic control elements. Always enter NO.*

Periodic report print. Entry Y for YES or N for NO to specify whether you want periodic traffic metering reports to be printed locally.

Assign terminal type (ATT) worksheets D2A, B, C (Figures 4-27 through 4-29). This function assigns common equipment and defines those types used with more than one terminal. These include conference bridges, the call service position, LKGs, and IMUs. These worksheets are in three sections. Section A is for conference bridges and the call service position SDMX/TDMX. Section B is for the loop key generators, and Section C is for the intermatrix unit.

DD Form 2490-16, Network Planning and Configuration Data--Conference Bridge and Call Service Position Worksheet (Figure 4-27). For the conference bridge, equipment type 95, make the following worksheet entries on worksheet D-2A:

Type. Enter 95. (See Table A-l.)

Unit number. Enter 1-6 to identify the bridge to be used.

In/Out of service. Enter I for IN or O for OUT, depending on equipment status.

Addresses. Enter the matrix location for each of the five ports. Use A-BB-CC for SDSG bridges and DD-EE for TDSG bridges. (See Tables A-3 and A-4.)

DD Form 2490-16, Network Planning and Configuration Data--Conference Bridge and Call Service Position Worksheet (Figure 4-27). For the call service position SDMX/TDMX, equipment types 96 and 121, make the following worksheet entries on worksheet D-2A:

Type. Enter 96 or 121. (SeeTable A-l.)

Unit number. Enter 1-4. Enter 1 for the local and 2, 3, or 4 for remote CSPs, if used.

In/Out of service. Enter I or O.

Voice port 1 and 2. Enter two matrix locations for SDMX or TDMX voice ports. (See Tables A-3 and A-4.)

TDMX signal term. This entry identifies the TDMX terminal that the CSP will use for signaling. Use format DD-EE. (See Table A-3.)

Directory number. Use the format GX1X or GX1XX in which X1 is not 0. This will enable a caller to route a call to the operator by dialing GOX or GOXX. Do not use the format GOXX for any terminals.

Digital receiver unit number. Use 1-5 to identify the digital receiver to be used. (See Table A-3.) The selected receiver must already be assigned and marked out-of-service.

DD Form 2490-17, Network Planning and Configuration Data--Loop Key Generator Worksheet (KG-82, Type 123) (Figure 4-28). For loop key generator worksheet (KG-82, type 123), make the following worksheet entries on worksheet D-2B:

Equipment type. Enter 123.

Unit number. Use 1-64.

In/Out of service. Enter I or O.

Cipher/plain terminals. Enter locations in format DD-EE (See Table A-3.)

DD Form 2490-18, Network Planning and Configuration Data--Intermatrix Unit Worksheet (Type 98) (Figure 4-29). The intermatrix unit worksheet (type 98) provides analog-to-digital and digital-to-analog conversions between the SDMX and the TDMX. Worksheet D-2C entries show which IMUs are connected.

Equipment type. Enter 98.

Unit number. Enter 1-120.

In/Out of service. Enter I or O.

SDMX terminal. Enter address location in format A-BB-CC. (See Table A-4.)

TDMX terminal. Enter address location in format DD-EE. (See Table A-3.)

Assign terminal services (ATS) worksheets D-3A, B, C. (Figures 4-30 through 4-32). Use these worksheets to assign classmarks to terminals using the terminal services function. These classmarks identify types of equipment, equipment characteristics, and available services. Be careful not to classmark a terminal unless the DTG associated with that terminal is in service. Use the ADT command to check this. The ATS command is also used to define loops, trunks, and signaling equipment. These worksheets are in three sections. Section A is for signaling equipment, Section B is for analog loops and trunks, and Section C is for digital loops and trunks.

DD Form 2490-19, Network Planning and Configuration Data--Signaling Equipment Worksheet (Figure 4-30). For signaling equipment worksheet, make the following entries on worksheet D-3A:

Terminal address. Use Tables A-3, A-4, and A-5 for these addresses. Tables A-3 and A-4 show the addresses by matrix, and Table A-5 shows signaling and common equipment addresses.

Terminal type. Enter 99,110-116, or 119. (See Table A-l.)

Unit number. This entry assigns the receiver and sender units. (See Tables A-3 and A-4.) Enter 1-32 for types 99 and 110-115, and 1-16 for type 116. (See Table A-l. Type 119 has no unit number.)

In/Out of service. Enter I for IN or O for OUT to reflect current equipment status reports.

DD Form 2490-20, Network Planning and Configuration Data--Analog Loop and Trunk Worksheet (Figure 4-31). For analog loops and trunks use worksheet D-3B. This worksheet and the one following, D-3C, are based on the planning worksheets P-1 and P-3. Some of the information on D-3B and D-3C repeat that in P-1 and P-3, but they are used for somewhat different purposes. The planning worksheets allow the gathering of data and are a master list. They become the basic source for information. Worksheets D-3B and D-3C relate that information to specific data entries. Worksheet D-3B also has strapping information for the NWLTU, for the master panel (SEP) number in the shelter to which the cable is connected, for the SDSG number, and for the specific cable number. On the left side of the worksheet there are common entries for both loops and trunks. These are:

CCSD/circuit number. Enter the system and/or circuit number assigned by the CSPE. The entry should be sufficient to identify the circuit. Use common channel signaling data (CCSD) in joint applications.

Cable pair. This column enables you to assign the circuit. to a pair or to two pairs of a 26-pair cable. If the circuit is 2-wire, delete the unused pair number.

Office designation. This is the unit or subscriber designation.

Type circuit. Enter trunk, local, or long local.

Type equipment. Enter nomenclature of terminal equipment.

Technical characteristics. Enter 2-wire or 4-wire, supervision (AC or DC), common battery or local battery, and signaling characteristics.

LTU type. Enter type of LTU.

LTU strap. If a NWLTU is used, enter strapping from worksheet S-4 and from the bottom of the worksheet.

Card location. Enter card slot location of LTU. (See worksheet P-3.)

Adapter type/location. If an adapter is used, enter type and card slot location. (See worksheet P-3.)

For analog loops use the headings on the top of the worksheet. If the loop is for DAS make only the entries under the block labeled DAS. Make these entries:

Terminal address. Use Tables A-3, A-4, and A-5 for these addresses.

Terminal type. (See Table A-l.) The terminal type will determine the next entries.

Directory number. Enter GXX(X) to show which subscriber is to receive service. Use this entry for types 1-3 and 5-13.

Line hunting group. Enter 1-32 if the terminal is a member of a line hunting group. If not, enter O. (See paragraph 3-7.) Use for types 1-3 and 5-13.

DAS called number. If direct access is available to the subscriber, enter the directory number to be called. To make it easier to account for DAS numbers you can use a separate worksheet for DAS subscribers. Use this entry for types 1-3 and 5-13.

Traffic load control. Enter 1-5 to specify level of busy hour restrictions. (See paragraph 3-7.) Use for types 1-3 and 5-13. See Table A-6 for the relationship between subscriber classmarks and trunk and switch restrictions.

Secure call. For types 1,2,5,7-9,12, and 13, enter R for REQUIRED or N for NONSECURE. For type 3, enter R for REQUIRED, P for PREFERRED, or E for END-TO-END. For type 6, enter R for REQUIRED, P for PREFERRED, or N for NONSECURE. This classmark determines the way the call will be routed. (See paragraph 4-7 for explanation.)

Maximum precedence. Enter FO, F, I, P, or R to show the maximum precedence allowed for subscriber calls. Use for types 1-3 and 5-13.

In/Out service. On the basis of the switch status reports, enter I for IN or O for OUT. Use for types 1-3 and 5-13.

Adapter number. Enter 1-24 for the 300-line switch and 1-36 for the 600-line switch. Use for line type 6 equipment on an analog loop. Otherwise leave blank.

Progressive conference. Enter Y for YES or N for NO to show whether the subscriber will receive this capability. This capability may not be available in your switch. In this case, enter N.

Call transfer. Enter Y for YES or N for NO to show whether the subscriber will receive this capability.

Compressed dial classification. Enter C for COMMON POOL, I for INDIVIDUAL LIST, or N for NONE to identify the subscriber as having access.

Compressed dial list. Enter 1-5 to show which list of common pool numbers is available to the subscriber, or 1-8 to show which subset of the individual list is available. Use 0 for NONE.

Zone restriction. Enter O for NONE or 1-8 to assign zones (lists) to which the subscriber is restricted. (See worksheet AZR.)

Preprogrammed conference only. Enter Y for YES or N for NO to show whether the subscriber is limited to preprogrammed conferencing.

Commercial network access. Enter Y for YES or N for NO to show whether the subscriber will have access to a commercial network.

For analog trunks use the headings on the bottom of the worksheet. Note that all types use the first seven entries but interswitch trunks with equipment types 28 and 29 use the block marked 39 trunk. Extraswitch trunk terminals using equipment types 25-26 and 30-83 use the block marked NON-39. Make the following entries:

Terminal address. Use Tables A-3, A-4 and A-5.

Terminal type. Use Table A-1. The terminal type will determine the entries. For interswitch trunks, equipment types 28 and 29, make the following entries.

TGC number. Enter 1-127.

Path delay. Enter 0-40 in steps of five for milliseconds of path delay. This is used for line-of-sight radio, troposcatter radio, and cable and is based on technical characteristics of the transmission media. It activates echo suppressors external to the switch. Use this classmark at the switch closest to the 2-wire party for a 2-wire to 4-wire connection. Use at both locations for a 2-wire to 2-wire connection.

TSB number, master/slave for type II modem. This is an optional entry and is not part of the data entry process. Enter the number of one of the TSBs, (3,4,5, or 6) to be used for analog CCS.

Satellite trunk. Enter Y for YES or N for NO. This adds a control indicator to outgoing calls to tell a terminating switch whether or not to introduce echo suppressors. (See ASC worksheet.)

In/Out of service. Enter I for IN or O for OUT.

Trunk number. Enter 1-255 to identify the trunk. (Trunk numbers will only be entered for interswitch or DIBTS trunks.)

16kbs trunk. Enter Y for YES or N for NO to show whether the trunk is assigned this rate.

MS trunk. Enter Y for YES or N for NO to show whether the trunk terminates at a AN/TYC-39.

MS trunk characteristic. If the trunk is an MS trunk, enter 1-15 for analog or O for digital.

Transmission type. If the trunk is not an MS trunk, enter AN for analog nonsecure, AS for analog secure, or DN for digital nonsecure.

Adapter number. Enter 1-24 or 1-36 to assign an SF adapter for an analog trunk.

Echo suppressor. Enter 1-120 to identify a specific item of equipment. If none, enter O.

For DIBTS equipment, equipment type 27, enter TGC number, path delay, satellite trunk, in/out of service, and trunk number.

DD Form 2490-21, Network Planning and Configuration Data--Digital Loop and Trunk Worksheet (Figure 4-32). For digital loops and trunks use worksheet D-3C. The layout of this worksheet is similar to D-3B. The common entries are on the left. Strapping information is at the bottom. Refer to worksheets S-8 and S-9 for these. The common entries have the same instructions except for the last one. Instead of adapter type and location enter:

NCMD number and location. This is the nine channel multiplexer/demultiplexer card. Enter which card is used and its card slot location.

For digital loops, the entry instructions are the same for the DAS subscribers. Other entries are:

Terminal characteristic. Enter D for Data Only, V for Voice Only, or M for Multi-Use to show the use of the terminal. Use for type 3 only.

16 kbs HDX. Enter Y for YES or N for NO to show whether a DSVT is to be used in the push-to-talk mode (use with net radio). Use for type 3 only.

MS compatible. Enter Y for YES or N for NO to show whether the DSVT is to connect to a message switch. Use for type 3 only.

Facsimile. Enter Y for YES or N for NO to show whether facsimile is to be used. Use for type 3 only.

MS type 2. Enter Y for YES or N for NO to show whether the DSVT is to connect to a type 2 message switch. A type 2 message switch is other than a AN/TYC-39 (for example, the unit level message switch (ULMS) AN/GYC-7). Enter Y only if the MS compatible entry was Y. Use for equipment type 3 only (Table A-l).

The remaining entries have the same instructions as D-3B. For digital trunks the instructions are also the same except that there is no NON-39 block.

Assign switch classmark (ASC) worksheet D-4. Worksheets D-1 and D-4 are combined on one worksheet. Refer to previous discussion about worksheet D-1/D-4 (Figure 4-26).

DD Form 2490-22, Network Planning and Configuration Data--Digital Transmission Group Worksheet (Figure 4-33). Assign digital transmission group (ADT) is a command on worksheet D-5. Digital transmission groups (DTG) contain trunk groups and loops. This command assigns, modifies, or deletes these or updates their characteristics. Make the following worksheet entries:

DTG number. Enter 1-16 to indicate the number of the group.

Message switch DTG. This entry indicates whether or not the group is from an MS. Enter Y for YES or N for NO.

Start NCMD/end NCMD. These entries assign NCMD units to a DTG. The number you assign must be compatible with the trunking used in worksheet P-2. Use 1-16.

KG-81. This indicates which trunk encryption device will be assigned to the group. Refer to FM 24-27A. Enter 1-6 (or 0 for no trunk encryption).

Sync delay. This indicates whether or not circuit conditions will require a delay to achieve synchronization. Use either 0 for no delay or 0.5 (seconds). Use the latter for troposcatter and satellite links.

In/Out of service. Enter I for IN or O for OUT. Marking the DTG out of service makes all the terminals in the DTG unavailable.

Auto sync desired. This entry specifies whether or not the switch requires synchronization for out-of-service DTG testing. Enter Y for YES or N for NO. The usual entry is Y.

Planning information. These entries are not part of the data entry process. They assist the planner and the switch supervisor in recording information relating to each DTG.

DD Form 2490-23, Network Planning and Configuration Data--Trunk Group Cluster Worksheet (Figure 4-34). Assign trunk group cluster (ATG) is a command on worksheet D-6. A trunk group cluster (TGC) consists of more than one trunk between two switches. Clustering of these trunk groups enables the switch processor to treat them as an entity when making assignments or when defining their characteristics. This command makes it possible to assign, modify, or delete characteristics throughout the cluster. Make the following worksheet entries:

TGC number. Assign a number from 1 to 127 on the basis of the network routing plan. See worksheets P-2 and P-4.

Cluster type. This entry classifies the TGC according to the kind of switch at the other end. Enter:

C   for commercial connection.

I   for interswitch connections to AN/TYC-39s, and to other AN/TTC-39s and

P   for PBX or PABX connections. In general, any switch that requires operator
     assistance to access the AN/TTC-39 is a PBX.

D   for DIBTS when used between crypto net control station and subscriber switches.

O   for other uses, such as connection to an AN/TTC-38 or AN/TTC-30.

Spill forward. This only effects intermediate (tandem) switches. Enter Y for YES or N for NO for inbound traffic only. See paragraph 4-7 for an explanation of this control. Always use this when crossing NYX boundaries.

Destination. NYX. Enter an NYX code to define the area code at the TGC destination.

Zone restriction. The AZR worksheet defines eight zone restriction tables. Enter 1-8 if this TGC pertains to any one of these tables. Enter 0 if there is no restriction.

Access TGC. An access TGC is one that provides the only connection from your network to a certain switch. Use this classmark to tell the calling switch not to try alternate routing if the access TGC is busy. Enter Y for YES, or N for NO.

Traffic limits. Enter Y for YES or N for NO to indicate whether any trunks in this cluster are restricted to precedence traffic. If YES, enter under each of the precedence columns in descending order (F, I, P, and R) the number of trunks (0-255) for which the precedence level applies. For example, if the TGC has 10 trunks, entries may be F = 10, I = 8, P = 6, R = 4. If no, leave these columns blank. (If your entry is C or O, make no further entry.)

If the entry under type is I for interswitch, make the following entries:

Key change. Do not use this entry. Enter N for NONE.

Glare. See paragraph 3-7 for an explanation of glare. Enter A for ACCEPT or R for REJECT of glare conditions. You must classmark switches at either end of this TGC so that one accepts and one rejects glare.

TSB number. This entry assigns a TSB to the TGC to provide CCS. (See worksheet P-4.) Enter 1-14 for a 300-line switch or 1-28 for a 600-line switch.

Message switch TGC. Enter Y for YES or N for NO to show if the TGC goes to an MS. Only one MS can be connected.

Call inhibit. Enter Y for YES or N for NO to indicate whether the call inhibit function is in effect for the area in which the destination switch is located.

Digital TSB TDMX address. If the TSB is digital (on a digital TGC), enter the TDMX address from Table A-3.

Primary/secondary signaling channels. If the TSB is digital, enter the TDMX addresses of the primary signaling channel and of up to 3 secondary channels.

If the entry under type is P for PBX, leave the interswitch cluster columns blank and make the following entries in the PBX cluster columns:

Number of outgoing digits. Enter 0-10 to show the number of digits needed for routing at the distant switch.

Maximum precedence. Enter FO, F, I, P, or R to show the highest level of precedence accepted at the PBX.

Switch code. Enter NNXX for the switch code of the switch being routed to.

Traffic load control level. Enter 1-5 to show the busy hour restrictions. (See paragraph 3-7 and Table A-6.)

If the entry under type is D for DIBTS, you will make only limited entries after the traffic limits entry. These will include entries for maximum precedence, traffic load control, glare, call inhibit, and destination switch code. Also fill in the last column as follows:

Commercial network access. Enter Y for YES or N for NO.

DD Form 2490-24, Network Planning and Configuration Data--Essential User Bypass Worksheet (Figure 4-35). Assign essential user bypass configuration (AEU) is a command on worksheet D-7. The essential user bypass (EUB) capability provides for automatically transferring certain subscribers to another circuit switch if the parent switch fails. EUB can accommodate up to 60 digital users. Make the following worksheet entries:

Subscriber. Identify the user by title or name. This entry does not go into the data base.

Subscriber number. Make this entry for identification. Again, it will not go into the data base.

From/To. Enter the TDMX addresses in the format DD-EE. Under FROM, enter the current address of the subscriber. Under TO, enter the route out of the switch to the trunk dedicated for this purpose. Check the ATS worksheet to make sure that these entries are consistent. Each EUB subscriber will require a dedicated trunk.

DD Form 2490-25, Network Planning and Configuration Data--Assign Key Location Worksheet (Figure 4-36). The assign variable key location (AVL) is a command on worksheet D-8. The AVL function assigns and modifies the data in the automatic key distribution center. Use this function for rekeying operations for COMSEC subscribers, for local and essential user DSVTs, and for message switch trunk LKGs. You can also use it for changing data base information without going through anew rekeying operation. Make the following worksheet entries:

COMSEC ID. This is the hardened unique store (HUS) location in the automatic key distribution center.

Directory number. Enter the subscriber's directory number or, in the case of a message switch trunk LKG, the matrix address. Leave this entry blank if the type (see below) is common interface rekey (CIR) or reentry home (RH).

Type. Enter 2-4 characters. This is the code which stands for the type of key in the HUS location. See FM 24-27A.

Net number. See FM 24-27A for information on this number.

DD Form 2490-26, Network Planning and Configuration Data--Net Rekeying Worksheet (Figure 4-37). Assign net rekeying (ANR) is a command on worksheet D-9. This command rekeys up to 15 COMSEC nets automatically. The nets must be of the same type and must consist of local DSVTs, those affiliated with subordinate switches, essential users, or message switch trunks.

Make the following worksheet entries:

Method. Enter G to generate a new net or M to merge nets.

Rekey cycle number. When starting or initializing (cold start), use 00. For subsequent rekeying, use sequential numbers from 01 through 99.

Current net number. Enter 2-98 to record the new number. Get this number from the COMSEC worksheets.

New net number. If a number has not yet been assigned, enter 2-98 to assign a new number.

(For additional information see FM 24-27A.)

DD Form 2490-27, Network Planning and Configuration Data--Commercial Network Routing Worksheet (Figure 4-38). Assign commercial network routing (ACN) is a command on worksheet D-10. Use this command to assign routing to a commercial telephone network. Make the following worksheet entries:

Primary TGC. Enter 1-127. To determine your entry, see the network routing plan. This shows how to make commercial connections.

Alternate. You may designate up to five alternate TGCs.

DD Form 2490-28, Network Planning and Configuration Data--NYX Routing Worksheet (Figure 4-39). Assign NYX routing (ANY) is a command on worksheet D-11. The NYX code is the area code. The switch uses NYX tables to route to other NYX areas. This command defines the trunk group clusters by which this is done. Make the following worksheet entries:

NYX code. Enter the area code to which routing will be done (N = 2 through 9). Use 9 only when interfacing with NATO countries.

Home/Foreign. Enter H for HOME on the first line to define your own area code. Enter F for FOREIGN on the other lines to define other than home codes.

NATO designation. If you are routing to a NATO switch, enter 9YX as the NYX code and specify the number of routing digits. Use S for SIX and T for THREE.

Primary TGC. Enter the selected primary route only for Foreign entries. Use numbers 1-127.

Alternate TGCs. You may list up to 5 alternates. Both primary and alternate listings must agree with the ATG and ATS worksheets.

DD Form 2490-29, Network Planning and Configuration Data--PR Routing Worksheet (Figure 4-40). Assign NN routing (APR) is a command on worksheet D-12. The NN routing tables contain routing data used by the switch to reach an NN (primary) area. The NN code is the first part of the switch code and defines the area in which the switch is located. You can also use it to define the home area of your switch if the 4/3 numbering plan is being used. Make the following worksheet entries:

NN code. Enter 22-99 to define the NN area for which routing is to be assigned.

Home/Foreign. Enter H for HOME or F for FOREIGN. Use H for your switch and F for all others. The use of H automatically defines the HOME code. You will need no other entry.

Primary TGC. For FOREIGN only, enter the trunk group cluster number, 1-127.

Alternates. You may assign up to five alternate TGCs for FOREIGN NN codes. Use 1-127. These entries are optional, but they must follow the network routing plan and be compatible with the ATG worksheet entries.

DD Form 2490-30, Network Planning and Configuration Data--NNX Routing Worksheet (Figure 4-41). Assign NNX routing (ANN) is a command on worksheet D-13. This command defines the primary and alternate TGCs to be used in routing calls between switches using the 3/4 number plan at the called switch. Make the following worksheet entries:

Switch code. Enter the switch code (NNX) of the switch to which you are routing.

Primary TGC. Use numbers 1-127 to identify the primary routing.

Alternates. If alternate routing is used, you may select up to five alternate TGCs.

DD Form 2490-31, Network Planning and Configuration Data--NNXX Routing Worksheet (Figure 4-42). Assign NNXX routing (ANX) is a command on worksheet D-14. You can use NNXX routing to conserve NNX codes when addressing a PBX or expanded switch. See paragraph 4-4 for an explanation of NNXX numbering plans. An expanded switch is one with a capacity increased to more than 600 lines. NNXX routing makes it possible for up to ten switches to share the same NNX code. The ANX command defines the primary and alternate TGC through which a call will reach the designated NNXX code. Make the following worksheet entries:

NNXX code. This entry identifies the NNXX code being routed to. For an expanded switch, the code becomes NNXG. Each NNXX table has a capacity of five groups of ten each for PBX routing and one group of ten that breaks down as follows:

NNXO - Operator

NNXX1 - Home code

NNXX2-9 - Expanded switches

Primary TGC. Enter 1-127 to designate the primary TGC.

Alternate TGC. You may list up to 5 alternates. Both the primary and alternate entries must agree with the entries on the ATG worksheet.

DD Form 2490-32, Network Planning and Configuration Data--XXX Routing Worksheet (Figure 4-43). Assign XXX routing (AXX) is a command on worksheet D-15. This function defines primary and alternate TGCs for routing to such XXX destinations as manual switchboards and PABXs. Make the following worksheet entries:

XXX code. Enter 100-999 to designate the XXX code being routed to.

Routing to operator. Enter Y for YES or N for NO to indicate if calls for the XXX code are to be intercepted and routed to the AN/'TTC-39 operator. If calls are to be extended by the operator, TGCs must be programmed.

Primary/Alternate TGC. Enter 1-127 to show the TGC through which a call will reach the XXX code. (See the ATG worksheet.) You may also enter up to five alternates.

DD Form 2490-33 Network Planning and Configuration Data--Alternate Area Routing Worksheet (Figure 4-44). Assign alternate area routing (AAA) is a command on worksheet D-16. Use this command to assign alternate area routing tables for areas to which multiple paths exist. Its use will increase the flexibility of the switch. It will also enhance the ability of the switch to complete calls during periods of heavy traffic. Make the following worksheet entries:

Alternate area codes. These are 9YX, NYX, or NN. You may assign up to eight of these to specify the alternate areas to which calls can be routed.

Switch code or national access code (NAC). You may assign up to ten of these for each alternate area code. The formats are XXX in a 9YX table; NNX, NNXX, or NN in an NYX table; and XX in an NN table. Each area requires at least one switch code.

TGCs. Use TGCs to designate first and second preferred routes. The routing plans assign each TGC a number. Enter the appropriate numbers (1-127) here.

Paragraph 4-4 provides an explanation of the numbering plans.

DD Form 2490-34, Network Planning and Configuration Data--SL Routing Worksheet (Figure 4-45). Assign XX routing (ASL) is a command on worksheet D-17. This function defines the primary and alternate TGCs through which a call will reach an XX (switch) code. You can assign only XX codes associated with the home NN. Make the following worksheet entries:

XX code. This defines the switch to be routed to or the switch to be designated as home. Enter 00-99.

Home/Foreign. Enter H for HOME for the switch you are operating from. Enter F for FOREIGN for all others.

Primary TGC. For FOREIGN only, enter the identification number (1-127) of the trunk group cluster used for primary routing. (See the routing plan.)

Alternates. For FOREIGN only, you may enter up to five alternate TGCs. Use 1-127.

DD Form 2490-35, Network Planning and Configuration Data--Common Pool Compressed Dial Worksheet (Figure 4-46). Assign common pool compressed dial list (ACP) is a command on worksheet D-18. Compressed dialing enables subscribers to dial a 2-digit number plus C rather than a longer number. The ATS command enables you to assign subscriber numbers to one of five common pools or lists. Only those subscribers authorized access to a compressed dial list on the ATS worksheet can utilize the 2-digit plus C address to access subscribers listed on that compressed dial list. (A subscriber does not have to be a member of the compressed dial list in order to access members of the list.) Make the following worksheet entries:

List number. This establishes each pool. Enter 1 through 5 for the five pools.

Compressed dial number. You may assign up to 80 NX codes to each pool. Enter 20-99.

Directory number. Enter the telephone number for each compressed number.

DD Form 2490-36, Network Planning and Configuration Data--Fixed Directory Routing Worksheet (Figure 4-47). Assign fixed directory routing (AFD) is a command on worksheet D-19. With the fixed directory, roving subscribers and unite do not have to change telephone numbers when changing locations. This command assigns subscribers to the FDSL and assigns units to the FDUL. Make the following worksheet entries:

List type. Enter S for SUBSCRIBER or U for UNIT. (Use separate lists for each.)

Index code. This is the fixed directory telephone number. The format PXJXZ enables you to list up to 3400 subscribers. You can list up to 100 units using the format XXIXX, where the IXX digits are the last three of the directory number (NNXXXXX).

Directory number. Enter the standard 7-digit directory number of the unit or subscriber.

Signal forward. Enter F for FIXED DIRECTORY or S for STANDARD DIRECTORY to show which number will be forwarded. (See paragraph 4-7 for fixed directory routing information.) Use S for all unite and subscribers homed on your switch or when your switch is a gateway for other switches.

To reach a subscriber or unit in the fixed directory, dial 99 plus the 5-digit fixed directory number (PXJXZ for a subscriber, XXIXX for a unit). If you are dialing a subscriber, the switch will convert the number dialed to the 7-digit directory number. If you are dialing a unit, the switch will convert the first 2 digits of the fixed directory number (XX) to an NNXX. It will then add the last 3 digits (IXX) of the fixed directory number to create the 7-digit directory number. Review paragraph 4-4 for further information on numbering.

DD Form 2490-37, Network Planning and Configuration Data--Individual Compressed Dial Worksheet (Figure 4-48). Assign individual compressed dial list (AIC) is a command on worksheet D-20. Compressed dialing enables subscribers, if authorized, to dial a 2-digit number plus C rather than a longer number to access subscribers of the network. The ATS command allows you to authorize selected subscribers access to one of eight individual compressed dial lists. A subscriber can be a member of only one list, individual or common pool, but not both. Make the following worksheet entries:

Compressed dial number (CDN). Enter 20-99 for up to 80 assignments. Dialing these two numbers plus C (NX + C) will convert the CDN into a telephone number of up to 13 digits.

Directory number. Enter the subscriber's assigned telephone number.

Subsets. You can define eight subsets or groups of varying size for this list. In your entries, assign each CDN to one or more groups, according to the needs of the subscribers. Enter an X under the number of each group to which you wish to assign the CDN in question. When you enter the data into the switch, simply key in the marked numbers from left to right. For example, you will enter as 24568. This entry would enable the subscriber to dial all numbers in groups 2,4,5,6, and 8.

                        1   2   3   4   5   6   7   8
                             X       X   X X        X

DD Form 2490-38, Network Planning and Configuration Data--Preprogrammed Conference Worksheet (Figure 4-49). Assign preprogrammed conference list (APC) is a command on worksheet D-21. A subscriber may have authorization to initiate conference calls from a pre-programmed list. For the dual-shelter switch (600-line), this command assigns up to 20 subscribers to one of 20 lists or groups. The single-shelter switch (300-line) can accommodate only 14 subscribers per list. With this capability, the authorized subscriber dials the group number, and the switch automatically connects all numbers of the groups. Make the following worksheet entries:

Preprogrammed conference group number. Enter a number from 20 to 99 to identify the group.

Security required. Enter Y for YES or N for NO to indicate whether the group needs security. A Y entry means that member must have a secure terminal.

Member directory numbers. List the number of each member of the group. Not all members need be subscribers on the same switch, and a subscriber may be a member of more than one group. You may use up to 10 digits. Check the ATS worksheet to make sure that classmarks are assigned.

Initiate classmark. This entry, Y for YES or N for NO, authorizes any member to initiate the conference by dialing the group number. You must list at least one Y.

DD Form 2490-39, Network Planning and Configuration Data--Digit Editing Worksheet (Figure 4-50). Assign digit editing list (ADE) is a command on worksheet D-22. Digit editing provides for modification of a telephone number to make it compatible with line and trunk types and with network numbering plans. This involves adding or deleting digits in specific portions of the NYX-NNXXXXX number. Up to 100 numbers may be so edited. Make the following worksheet entries:

Code. Enter the NYX, NNX, or NNXX code to be changed.

Equipment. At one time this entry assigned loop-around equipment to perform mode conversions in conjunction with the digit-editing process. This equipment is no longer used. Enter 0.

Edit type. Enter D for DELETE or P for PREFIX.

Prefix code. If you entered P in the preceding column, enter the NYX, NNX, NX, or N prefix code here. Otherwise, leave this column blank.

DD Form 2490-40, Network Planning and Configuration Data--Call Inhibit Lists Worksheet (Figure 4-51). Assign call inhibit list (ACI) is a command on worksheet D-23. Use this command when it is necessary to deny access to certain calling areas. With it, you can prevent groups of subscribers from calling restricted areas. You can also use it as a traffic control measure to channel calls to certain portions of the area. Make the following worksheet entries:

NYX area code. This identifies the area containing the codes to which you are restricting access. You may identify up to 20 of these areas.

Start NNX. This entry indicates the first of a series of numbers within the area to be restricted. In each NYX, you can assign up to 50 individual codes or up to 25 consecutive code groups. A code group is a block of NNX numbers.

End NNX. This entry indicates the last number of a consecutive group. Do not use it for individual codes.

E. Enter E to eliminate the NNX line entry when making changes.

DD Form 2490-41, Network Planning and Configuration Data--Secondary Traffic Channels Worksheet (Figure 4-52). Assign secondary traffic channels (AST) is a command on worksheet D-24. Some configurations involving digital group multiplex equipment will require that secondary traffic channels be identified. This increases the accuracy of call completion. To perform this function, you will assign secondary traffic channels to a terminal, to digital trunks, or to the loop group signaling channel. Use it for terminal types 3, 13, 27, 29, and 119. (See Table A-l.) Make the following worksheet entries:

Terminal address of primary traffic channel (PTC). Enter the terminal address of the PTC, XX-XX.

Secondary traffic channel (STC). Enter the terminal address of each secondary traffic channel. You can list up to three. You must assign either one or three STCs to each PTC.

In/Out of service. Enter I for IN or O for OUT to show whether traffic channels are in service. If you mark a secondary channel In, you must also enter an In for the DTG associated with it. Use the ADT command to check DTG status.

DD Form 2490-42, Network Planning and Configuration Data--Zone Restriction Worksheet (Figure 4-53). Assign zone restriction (AZR) is a command on worksheet D-25. Zone restriction is a means of traffic control. Zone restriction lists can be either restrictive (in which the code listed may not be called) or permissive (in which only the codes listed may be called). The AZR worksheet identifies makeup of zone restriction lists. The ATG command classmarks TGCs and the ATS command classmarks loops to a zone restriction list. Two of the eight lists can holdup to 101 entries each. The others hold up to 33 entries each. Make the following worksheet entries:

List number. Enter 1-8 to identify list.

Permissive/restrictive. Enter either P or R.

Start code. Enter NYXNNX, NNXXXX, NYX, or NNX to show the first of a consecutive list of numbers. You can also list a single number.

End code. Enter the last number of each consecutive list. If you entered a single number under start code, you must also enter it here.

Eliminate. Use E to delete data on the line. Leave blank if you are not deleting data.

DD Form 2490-43 Network Planning and Configuration Data--Assign Received Bypass Worksheet (Figure 4-54). Assign received bypass list (ARB) is a command on worksheet D26. Use this command in conjunction with the AAR command (assign, accommodate, and restore received bypass lists). This function can accommodate up to 60 EUs from each of two other switches. This command lists those users. When you have completed the list, the switch stores it until the AAR command activates it. Note that the presence of these EUs will reduce the capacity of your switch for local subscribers. Make the following worksheet entries:

Switch code. This is the switch code of the switch being bypassed. Enter NNX(X).

GXXX/GXX. List the subscribers by number. Enter GXX(X).

Matrix location. Enter the matrix address to which the EU will be assigned. Select this location from the interswitch digital trunks connecting to the bypassed switch.

Terminal type. Enter 3.

Security. Enter P for PREFERRED, R for REQUIRED, N for NONSECURE, or E for ENDTO-END ENCRYPTION REQUIRED. (See the ATS worksheet from the bypassed switch.)

Adapter number. Enter 1-36 for terminal types 6, 10, and 11 to assign adapters if needed. Otherwise leave blank.

This command will automatically classmark all EUs for FLASH precedence after list activation. It will classmark the DSVTs of EUs for multimode use. Refer to AVL command for DSVT information.

DD Form 2490-44, Network Planning and Configuration Data--Assign, Accommodate, and Restore Received Bypass Worksheet (Figure 4-55). Assign, accommodate and restore received bypass list (AAR) is a command on worksheet D-27. Use this command in conjunction with the ARB command. This function activates (accommodates), deactivates (restores), and adds (assigns) lists of EUs from two other switches. When activated, those subscribers of the other switches become local loops to your switch until deactivated. Make the following worksheet entries:

Switch code. This is the received (or bypassed) switch. Enter NNXX or NNX. Note that this menu must be rekeyed for the second switch.

GXXX/GXX. Use only to add new subscribers. Enter those subscribers' numbers.

Matrix location. Use only for new subscribers. This is the matrix location to which the incoming EUs are assigned. Use formats A-BB-CC or DDEE. (See Tables A-3, A-4, and A-5.)

Terminal type. This is also for new subscribers. Use 1-3 and 5-13. (See Table A-1).

Security. This is also for new subscribers. Enter P for PREFERRED, R for REQUIRED, N for NONSECURE, or E for ENCRYPTION REQUIRED. This determines how routing is done. (See paragraph 4-7.)

Adapter number. This is for terminal types 6, 10, and 11. Enter 1-36. (See Table A-1.)

Deactivating the lists deletes all new subscribers added in this way.

DD Form 2490-45, Network Planning and Configuration Data--Assign Frequency for Network Reporting Worksheet (Figure 4-56). Assign frequency for network reporting (AFR) is a command on worksheet D-28. Use this command to set the reporting interval for traffic metering reports. The worksheet lists codes for the various reports and times which can be used. Refer to paragraph 3-14 for explanation of the reports. Make the following worksheet entries:

ID. Enter one of the numbers listed identifying the reports R3, R4, R5, R6, R27, R44, and R47.

Frequency adjustment. Enter one of the numbers listed identifying the time. If the frequency adjustment is left blank, the switch will assign the longest interval.

DD Form 2490-46, Network Planning and Configuration Data--Thresholds Worksheet (Figure 4-57). Assign variable thresholds (ATH) is a command on worksheet D-29. Use this command to assign and change the values assigned to time-out limits. This worksheet lists those time-outs and the range of times and calls which can be used for each. The normal entry should be used if no information is available on which to base other limits. Each entry is explained as follows:

Dial tone time-out. The time limit after receipt of dial tone until the first digit is received.

Next digit time-out. The time allowed to a sub-scriber between the dialing of each digit.

Release time-out. The time the switch has to send a tone or a message.

Ring/ringback time-out. The time to send ring or ringback after completion of a connection.

Lockout state out-of-service time-out. The time between release time-out and marking an off-hook terminal out-of-service.

Precedence violation announcement time-out. The time the switch has to send a precedence violation message.

Traffic load control time-out. The time period to measure traffic to determine load control thresholds.

Traffic load control thresholds. The number of calls during the specified time period before load controls are activated.

Enter the time or call number next to each time-out or threshold. Table 4-19 below provides data for the other time-out number entry. List the number and the time to activate one of these numbers.

DD Form 2490-47, Network Planning and Configuration Data--Traffic Metering Worksheet (Figure 4-58). Assign traffic metering (ATM) is a command on worksheet D-30. Use this command to set the reporting interval and to designate the loops and TGCs to be monitored. The entries are:

Modify. Enter 1 to display current valve; 2 to change the loop report interval and/or the loop number; 3 to change the TGC number; and 4 to change loops and trunks.

Loop report interval. Enter one of the time intervals (15, 30, 60, 240, 480, 1,440 minutes).

Loops. Enter the matrix address in the format A-BB-EE for analog and DD-EE for digital. (See Tables A-3 and A-4.)

TGC. Enter the TGC number 1-127.

Sequence of data entry.

After the data worksheets have been filled out or the switch has received them from the CSCE or the planner, assemble them in entry order. This is generally the order in which they are numbered, with the exception of D-3. Use Table 4-20 as an assembly guide and a checklist to show that the entry was made. If any ramification messages result, you can also note them here for later analysis.

4-7. Routing

The earlier parts of this chapter described how the switch operates and how the data base is built. This paragraph gives you a detailed description of the routing function. With it, you can develop the routing plan described in paragraph 5-6. This routing plan is put together at the highest planning level in the network to make sure that all routing is coordinated. From this master plan each lower level adapts its planning. The following factors affect the routing process, and they are explained below:

  • Trunking.
  • Number plans.
  • Routing tables.
  • Precedence.
  • Routing controls.
  • Special features.
  • Routing to other networks.


Trunks are channels between switches. Grouping of trunks is analog and digital; that is, into digital trunk groups and analog trunk groups. These are further grouped by clusters. TGCs may be of mixed types. The types are based on security capabilities and transmission types in the following combinations:

  • Digital/nonsecure.
  • Analog/secure.
  • Analog/nonsecure.

The switch selects one of the trunks in a TGC for a particular call depending on the factors listed above and on the classmarks that you assigned in the data entry process (paragraph 4-6). For example, the switch will not route a call from a terminal classmarked Secure Call Required over an AN trunk. The originating terminal and the type of call are also factors in trunk selection. Using digital trunks for an analog call causes some degradation because of the analog-to-digital conversion. Some calls are more restrictive. For example, data calls may not be converted. The switch does not recognize analog data calls except from a AN/TYC-39. Others are treated as voice calls and will go over analog trunks only if the 3C prefix is keyed. Digital data calls go over digital trunks only.

When a circuit switch routes a call to its connected message switch (AN/TYC-39), other trunk selection rules apply. For an analog call, the circuit switch selects a trunk compatible with such data characteristics as modem type, COMSEC equipment, and COMSEC key. On a call from a data subscriber, the switch translates data characteristics from the called loop number. On a call between message switches, the call initiate message carries this information.

Numbering plans.

Review paragraph 4-4. It shows how the numbering plan reflects the network routing plan. Paragraph 5-6 shows how you will organize your nodes and their interconnections. The end result of this will be the assignment of PRs, switch locations, and area codes.

Routing tables.

The AN/TITC-39 uses routing tables as its basic reference for sending calls. These tables are organized by the data entries you made on worksheets D-10 through D-17. The specific entries depend on the organization of the network as defined by the routing plan and the number assignments. For each switch code and for each area code, you must designate a primary TGC. You may designate up to five alternate TGCs. The number of alternates depends on your routing plan and the needs of your networks. When a call is dialed, the originating switch scans the primary TGC for an idle trunk. If none is available, it scans each alternate TGC in order. The kind of routing depends on the number dialed and on the destination. Calls within your own PR will use XX (SL) routing. Calls to another PR but in the same area code use NN (PR) routing. Calls to a number in another area code use NYX routing. Calls to a switch not using the TTNP or PRSL numbering plan use NNX routing and follow the same area routing rules. This enables you to use the 3/4 numbering plan to route to a switch. Calls to manual switchboards use XXX routing.

When multiple paths exist to an NYX or PR area, select routing based on the NNX or PR code for NYX areas, and select the SL code for PR areas. (See worksheet D-16.) There are eight alternate area tables for each switch. You can assign each one to one NYX or PR. You may then assign up to ten switch codes, subarea codes, or national access codes per table. In this case, the switch routes over a primary or alternate (first preferred and second preferred) route. Designate these on worksheet D-16.


Another factor in trunk selection is the call precedence dialed by the caller. The switch will search all available trunks in the sequence described above to find an idle trunk. If none is found and if the call precedence is greater than ROUTINE, the switch conducts a preemptive search in the same sequence. This continues up to one level below the precedence of the call. If a trunk is found, the switch will preempt it for the caller. If not, the switch will return a busy signal.

Routing controls.

If the network uses intermediate (tandem) switches to route calls to their destinations, you can apply certain controls. The originating office control means that the originating switch retains control of the call. For example, take the case of an intermediate switch that has tried all its routes with no success. This control will return the call to the originating switch, thus enabling it to try an alternate route.

Spill forward control is used for calls coming into a switch which will need further routing to reach their destination. The switch acts as an intermediate switch for these calls. If the TGC is classmarked for spill forward, the switch assumes complete control for all calls coming in on that TGC that require routing and acts as an originating switch. However, alternate routing is no longer available to the switches through which the call has passed. This prevents calls from being routed back to the area or network from which they come. If a route is not found, the switch sends an all-trunks busy signal back to the caller. Always use this control at gateways and when crossing NYX boundaries. Worksheet D-4 enables you to classmark the switch for alternate routing. In general, always mark for alternate routing. Withhold alternate routing only if you want to limit the use of trunk calling.

Other routing controls include call inhibit, zone restriction, TGC traffic limitations, restrictions on the use of satellite trunks, and load controls. Paragraph 3-7 described each of these. An additional control (or protection) is the ability to detect a routing loop. If a call is routed back to its origination (sometimes called ring-around-the-rosy), an alarm will alert the supervisor. A message will also appear on the printer. With this information, you can reconfigure the network to prevent the routing loop. Usually a change in routing will do the job.

Special features.

The special features of the AN/TTC-39 have a direct effect on routing. Paragraph 3-7 describes these features. Paragraph 4-4 shows how to activate them, and paragraph 4-6 shows how to classmark them. They include direct access, conferencing, compressed and abbreviated dialing, call transfer, and fixed directory. Use these features very care-fully because their use may affect the service provided by the switch.

When a fixed directory code is dialed, the switch must look at the fixed directory table to determine how to route the call. This will occur at each switch through which the call is routed. The call is routed on the standard (or system) directory number, not on the fixed directory number. If the subscriber or unit has the classmark F for fixed directory number forward (see worksheet D-19), each switch checks the table and routes the fixed directory number accordingly. When the call reaches the current home switch for the subscriber or unit, the classmark S for standard directory indicates that routing should stop. The call is then connected locally. The last AN/TTC-39 in the route should also have the classmark S if the fixed directory call is routed to any other type of switch.

Routing to other networks.

Worksheet D-4 also enables you to classmark a switch as a gateway. If a primary TGC connects to a switch other than an AN/TTC-39, that switch is a gateway. This classmark enlarges the scope of trunk selection. It also provides for analog-to-digital conversion so that analog switches may receive and transmit calls. The dialing sequences in paragraph 4-4 describe commercial network routing. Use worksheet D-10 to assign commercial routing. The use of prefixes controls AUTOVON and other DCS routing. (See paragraph 4-4.)

NATO and allied routing is via the international access code (IAC), 9YX, followed by a 10-digit subscriber number. The switch then routes the call on the IAC and the NAC if listed. NATO systems are classmarked for either a 3- or 6-digit routing capability. If the connecting network uses 6-digit rules, the address is forwarded to that network. The procedures different if the connecting network uses 3-digit rules and if the call is to terminate in that network or is to go to a network that also uses the 3-digit rules. The gateway AN/TTC-39 strikes off the NAC but retains the IAC. If the call has to transit the 3-digit rule network to reach a 6-digit network, the AN/TTC-39 forwards the address as dialed. Any call that is from a US subscriber to another US subscriber but that has to transit a NATO network must use the NAC. If the caller does not dial the NAC, the designation is added by the gateway switch.

When publishing instructions for using the circuit switching system, make sure that you include information on how to call other networks. You can include this in a telephone directory, an SOP, or the CEOI. The telephone directory can also be part of your network or unit SOP or part of the CEOI.

4-8. AN/TTC-39A Application

Although the basic data entry process is not changed by the AN/TTC-39 modification, there are several new commands related to the channel assignment function. These are:

Assign channel reassignment (ACR).

The ACR data entry input shows the DTG number and channel number, channel range, or subgroup number for each channel or group for each reassignment.

Display channel reassignment (DCR).

The DCR command shows all channel reassignment from the subgroup, channel range, or channel number to the DTG number and the subgroup, channel range, or channel number.

Digital transmission group (DTG).

The DTG command displays for each DTG number the multiplex signal format and the group rate. For each channel it shows the channel number, the TDMX address, the terminal type, the status (primary or secondary), and the subgroup number.

Display individual channel reassignment function.

The display individual channel command displays for each DTG the channel number and the TDMX address before and after the channel reassignments. Inputs are started with the TDMX address from which the reassignments were started.

Change to assign digital transmission group.

The existing ADT data entry has added inputs of multiplex signal format, group rate, and subgroup rates or number of channels.

*Changes to the switch software may eliminate these entries.

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