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APPENDIX B

DIGITAL MESSAGE DEVICES

Section I

DIGITAL MESSAGE DEVICE AN/PSG-2A

This section implements STANAG 2934, Chapter 13 Annex A and QSTAG 503.

B-1. OPERATION OF THE DIGITAL MESSAGE DEVICE

a. Description. The digital message device AN/PSG-2A is a small, rugged, lightweight, portable, two-way communications terminal. It is used by FA observers to transmit and receive high-speed digital messages. The DMD can communicate with the tactical fire direction system (TACFIRE), the BCS, the FIST DMD, the mortar ballistic calculator (MBC), and other DMDs through wire or radios. Mnemonics used with the DMD are listed and interpreted in Tables B-1 and B-2 at the end of this appendix (B-31 and B-32).

b. Data Entry and Message Composition. Information is entered into the DMD, and messages are composed by means of a keyboard and a display located on the front panel. Data entry menus and message formats are presented in an easily understood manner. Information is entered by using a step-by-step procedure. The DMD prompts the operator for proper entries by displaying all possible choices for each data or message element. Entries are made as direct data or as a multiple-choice selection from a displayed menu. Illegal entries are prevented. Completed data entry menus and messages are displayed for operator viewing so that errors can be identified and corrected. Some fields contain preset default values. The default is assigned if the operator selects no other value for that field.

c. Memory Capacity. The DMD memory has several buffers and files:

  • Four received message buffers.

  • One received message save buffer.

  • Two active mission buffers.

  • Seven off-line compose message files.

  • One authentication code file.

d. Functional Sections. The DMD AN/PSG-2A has four functional sections as shown in Figure B-1.

Figure B-1. DMD FUNCTIONAL SECTIONS

    (1) Control Section. The control section consists of indicator lamps, brightness control knobs, the operational mode switch, and the power switch.

      (a) Indicator Lamps. Figure B-2 shows the four DMD indicator lamps. Their purposes are as follows:

  • ACK Flashes two times per second upon receipt of an acknowledge (ACK) message and one time per second upon receipt of a nonacknowledge (NAK) message.

  • MSG 1: Flashes when a message is received. It flashes four times per second when an FO CMD message is received and one time per second when other messages are received.

  • MSG 2: Flashes when two, three, or four messages are stored in the received message buffers awaiting review. If the lamp is flashing four times per second, at least one FO CMD message has been received.

  • NAK: Flashes two times per second upon receipt of a NAK message and one time per second upon receipt of an ACK message.

      (b) Brightness Control Knobs. The two brightness control knobs are shown in Figure B-3. Their functions are as follows:

  • DSP BRT: Adjusts the brightness of characters on the display panel and the intensity of the indicator lamps.

  • KYBD BRT: Adjusts the brightness of the keyboard background. To save battery power, the keyboard brightness should be set at the lowest usable level.

      (c) Operational Mode Switch. The operational mode switch selects the DMD operational mode. It has three positions as shown in Figure B-3.

  • FAULT: Is used by maintenance personnel only. Operators are not authorized to use the FAULT position.

  • OPR: Places the DMD in the operating mode when power is applied.

  • TEST: Provides a check of the input power, the display, and all indicator lamps. Also, it enables the keyboard test.

      (d) PWR Switch. The power switch applies power to the DMD (Figure B-3). It has three positions:

  • EXT: Applies power to the DMD from an external source (vehicle or battery).

  • OFF: Turns off internal and external power.

  • INT: Applies power to the DMD from the internal battery pack.

    (2) Display Section. The display is a low-power, dot matrix plasma panel which can display 256 total characters on eight lines. It displays incoming messages; it enables the operator to compose, review, and edit messages before transmission; and it enables the operator to select and observe the operational status of the DMD.

Figure B-2. DMD INDICATOR LAMPS

Figure B-3. DMD CONTROL SECTION

    (3) Keyboard Section. The keyboard section (Figure B-4) has three functional areas: function keys, alphabetic and punctuation keys, and numeric keys.

Figure B-4. DMD KEYBOARD SECTION

      (a) Function Keys. These keys are used to perform operations associated with message reception and transmission, display of data and message fields, and cursor movements. Their functions are as follows:

  • XMIT. Transmits messages.

  • BELL: Silences the audible tone which can be made to sound upon message receipt.

  • LAMP: Turns off the indicator lamps.

  • *: Allows entry of the operator's key code for authentication codes.

  • JUMP: Causes the fields of a message format or data entry menu to be displayed for editing.

  • <-|->: Move the cursor in the direction indicated.

  • MSG: Causes messages stored in the received message buffers to be displayed in the order of their receipt.

  • LAST: Pages backward through the authentication code file or through the off-line composed message files and active mission buffers.

  • OFF: Turns off the display without losing data.

  • NEXT: Pages forward through the authentication code file or through the off-line composed message files and active mission buffers.

  • RCAL: Recalls the display after automatic or manual turnoff. To conserve power, the display automatically turns off if no key is pressed for approximately 24 seconds.

  • MODE: Displays the mode menu.

  • SAVE: Saves a received message.

      (b) Alphabetic and Punctuation Keys. These keys are used to enter alphabetic and punctuation characters for composing and editing messages. Alphabetic keys are also used to display message formats, to display messages composed in active mission buffers or off-line files, to display mission data, and to enter authenticator codes. Two special function keys are included among the alphabetic and punctuation keys:

  • Tn: Enables the entry of a try number in the header line display. It also serves as the alphabetic T key.

  • SPACE: Puts spaces in the text of a FREETEXT message.

      (c) Numeric Keys. Keys 1 through 0 and the sign keys (+ and -) are used to enter numerical data.

    (4) Interface Section. The interface and power connectors (Figure B-5) are located on the top left side of the DMD rear case. Their functions are described below.

  • The RADIO connector is used to connect the DMD to standard US Army radios and to Air Force and other amplitude-modulated (AM) radios.

  • The GLLD connector is used to connect the DMD to a G/VLLD.

  • The POWER connector is used to connect the DMD to an external power source.

  • The LINE connector (two binding posts) enables the DMD to communicate over standard field wire.

Figure B-5. DMD INTERFACE SECTION

e. Audible Tone. The DMD has an audible tone, or beep, which can be made to sound when a message is received and/or when a key is pressed. It can be set at different intensity levels. The audible tone sounds one time per second for regular messages, two times per second for ACK and NAK messages, and four times per second for FO CMD messages.

B-2. PREPARATION FOR USE

Before the DMD can send and receive messages, it must be prepared for use. Preparation includes the procedures discussed below.

a. Assembly. The manner in which the FA observer assembles his DMD is determined by the tactical situation, the observer's mission, and his method of operation.

    (1) Dismounted Operations. The DMD must be prepared for portable operation when the observer conducts dismounted operations. It can be operated from its carrying case, or it can be attached to and operated from a backpack. In either configuration, power must be applied from a portable power source This source normally is the internal battery pack, but an external battery may be used. To communicate, the DMD must be connected to field wire or to a radio set. If the observer has a G/VLLD, he may also connect the DMD to the G/VLLD via the interface cable.

    (2) Mounted Operations. During mounted operations, the DMD may be installed in its carrying case or it may be removed. In either configuration, the observer must position the DMD where it can be readily used. It must be secured and protected to prevent damage during vehicle movement. The DMD normally is powered by a vehicular power source and is connected to a vehicular radio.

b. Memory Purge. The DMD memory may be purged. Purging deletes all previously stored information in the DMD status menu, authentication code file, received message buffers, off-line compose message files, and active mission buffers. Any message or data element having a default will, be assigned that default value. The memory normally is purged only when it is necessary to completely reinitialize the DMD or under emergency conditions to prevent enemy access to stored information.

c. Diagnostic Checks. The DMD has built-in test circuits which enable the operator to determine the operational status of the DMD. Diagnostic checks may be made anytime. They should be made when preparing the DMD for use.

    (1) Display and Indicator Lamp Test. The operational mode switch is used to determine if power is properly applied to the DMD and if the DMD is functioning properly. This tests the display and indicator lamps.

    (2) Keyboard Test. When the display and indicator lamp test is completed, the DMD is placed in a special keyboard test mode. The proper functioning of each key can be verified at this time.

    (3) Operational Check. The communications interface may be checked for proper function by the operational check.

    (4) Message Bell Volume Test. The message bell volume may be set and tested.

d. Initial Status Selection. The status menu is used to establish certain communications parameters, DMD functional characteristics, and battery condition information. Most of the data fields have default values. The fields are discussed below.

    (1) ORIG. This field is used to establish the origin of messages transmitted from the DMD. The alphanumeric character that serves as the unique address (digital call sign) of the DMD is entered in this field. No default value is assigned.

    (2) DEST. This field is used to establish the destination to which messages will be transmitted. The unique address of the receiving device (TACFIRE, BCS, FIST DMD) is entered in this field. No default value is assigned.

    (3) T/D. This field is used to indicate whether a message transmitted from the DMD is a test message or contains data. Data is the default value.

    (4) XMT BLK. This field is used to select the transmit block mode employed by the DMD. If SNG is selected, then the message contents are transmitted once. If DBL is selected, the message contents are automatically transmitted twice. The single block mode is the default value. The transmit block selected is dictated by unit SOP or tactical conditions. The double block mode may be specified during periods of heavy radio interference or jamming. The DMD block mode must match the block mode specified in the destination device.

    (5) XMT RATE. This field is used to specify the rate at which the DMD will transmit and receive messages. 600 or 1,200 bits per second may be selected; 1,200 is the default value. The transmit rate selected is dictated by unit SOP or tactical conditions. The DMD transmit rate must match the rate specified in the destination device.

    (6) PREAMBLE. The DMD must key the radio or wire circuit before transmitting a message, just as radio operators must do. The preamble field specifies the amount of time the radio or wire circuit is keyed before message transmission. A value between 0.1 and 4.0 seconds may be specified; 2.2 seconds is the default value.

    (7) AUTH GROUP NO. This field is used to indicate the current group of authenticators. Group number 00 is the default value.

    (8) AUTH LINE NO. This field is used to indicate the line number of the authenticator pair that will be sent with the next message transmitted from the DMD. Line number 01 is the default value.

    (9) DSPL DLY. This field is used to specify the time the DMD will wait from the last data entry until the next display is presented. A value between 0.0 and 2.0 seconds may be specified; 0.4 second is the default value.

    (10) KBD BELL VOL. An audible tone can be made to sound when a key is pressed. The volume is set by selecting a value from 0 (completely off) to 7; 0 is the default value.

    (11) MSG BELL VOL. An audible tone can be made to sound when a message is received. The volume is set by selecting a value from 0 (completely off) to 7; 0 is the default value. This field is also used to conduct the message bell test.

    (12) WATT HRS. The DMD counts and displays the number of watt hours of power consumed from the internal battery. WATT HRS should be set at 00.0 when a fully charged battery is installed. There is no default value assigned.

    (13) BATT LMT. This field is used to indicate the total number of watt hours of power the operator believes the internal battery can produce. The DMD compares the values in this field and in the WATT HRS field to alert the operator to battery weak and battery required conditions. There is no default value assigned.

e. Entry of the Authentication Code List and Operator's Key.

    (1) Digital messages transmitted by TACFIRE, the BCS, the variable format message entry device (VFMED), the FIST DMD, and the DMD contain an authenticator pair and a try number. These entries enable messages to be self-authenticated. Authenticator pairs are extracted from an authentication code book and stored in the DMD authentication code file. When composing a message, the DMD operator can cause the DMD to transmit the proper authenticator pair with the message. See subparagraph B-5a(1)(a).

    (2) The operator's key is also stored in the DMD authentication code files. See subparagraph B-5a(1)(a) for information on the operator's key.

f. Establishment of Digital Communications. Once the DMD has been prepared for use, digital communications must be established with the destination device. Normally, voice communications are established first to ensure that all radios are operating and are properly set or to ensure the wire circuit is complete. Once this has been done, a FREETEXT message is transmitted to ensure that communications parameters have been properly set and that the DMD can transmit and receive.

B-3. DMD MESSAGE FORMATS

The DMD can transmit and receive 20 preprogrammed, fixed-format message types which are divided into five categories as discussed below.

a. Standard Fire Requests. Standard fire request messages contain all the information in a conventional call for fire:

  • Observer identification.

  • Warning order.

  • Target location.

  • Target description.

  • Method of engagement.

  • Method of fire and control.

They are used by observers to initiate fire missions. The five standard fire request messages are as follows:

  • FR QUICK (fire request, quick response): Used to request that TACFIRE or BCS assign a known point number to a previously stored target, to fire an FPF, to terminate firing an FPF, and to request fire on a known point or target which is stored in TACFIRE or BCS.

  • FR GRID (fire request, grid coordinates): Used to request fire by using the grid cocrdinatt s method of target location.

  • FR SHIFT (fire request, shift from a knc)wn point): Used to request fire by using the shift from a known point method of target locaticn.

  • FR POLAR (fire request, polar coordirLltes): Used to request fire by using the polar coordinates method of target location.

  • FR LASER (fire request, laser, polar coordinates): Used to request fire by using the laser polar coordinates method of target location. The DMD-G/VLLD interface enables the laser polar data to be transferred directly from the G/VLLD into the FR LASER message.

b. Adjustments. Adjustment messages contain all the information required for the adjustment of fire. The three adjustment messages are as follows:

  • SUBQ ADJ (subsequent adjustment): Used to adjust fires onto a target when an FR GRID, SHIFT, or POLAR. format was used for the initial request.

  • SA LASER (subsequent adjustment laser): Used to adjust artillery fires by using the GMLD when an FR LASER format was used for initial request. When the round impacts, the observer lases the burst, and the laser polar data of the impact location are entered into the SA LASER format. The TACFIRE and BCS use this information to calculate the necessary adjustment.

  • EOM&SURV (end of mission and surveillance): Permits the observer to end a fire mission, make refinements, report target surveiDance, and request that a target be recorded.

c. Registrations. Registration messages are used in observing a precision, an HB or MPI, or a radar registration. The three registration messages are as follows:

  • PREC REG (precision registration): Used to adjust the firing of a precision registration or destruction mission.

  • HB/MPI (high burst or mean point of impact): Used to report the spottings made in observing an HB or MPI registration.

  • RDR REG (radar registration): Used by a radar section to report the impact grid coordinates of rounds fired in a radar registration.

d. Intelligence. Intelligence messages are used to report enemy locations and other information of intelligence value. The three intelligence messages are as follows:

  • ATI GRID (artillery target intelligence, grid coordinates): Used to report enemy locations by use of grid coordinates.

  • ATIPOLAR (artillery target intelligence, polar coordinates): Used to report enemy locations by use of polar coordinates.

  • SHELREP (sheDing report, artillery target intelligence, crater analysis): Used by an observer to report information concerning the impact of enemy artillery or mortar fire at his location.

e. Information. Information messages can be transmitted and received by the DMD. The six information messages are as follows:

  • FIREPLAN (planned fire mission): Used by the observer to establish a planned fire mission.

  • FO CMD (forward observer command): Used by the observer to fire a mission established at his command and to order check firing. Also used by the FDC to report SHOT, SPLASH, and READY to the observer.

  • MTO (message to the observer): Used by the FDC to report fire mission data to the observer.

  • OBSR LOC (observer location, grid coordinates): Used by the observer to report his location to the FIST or FDC. Also used by the FDC to report the observer's location to the observer when the location is determined by resection or trilateration.

  • FL TRACE (frontline trace): Used by the observer to report the front line of troops of his associated maneuver element.

  • FREETEXT: For nonformatted messages.

B-4. MESSAGE COMPOSITION, STRUCTURE, AND FLOW

Messages may be composed in the active mission buffers or in the off-line compose message files.

a. Message Composition in Active Mission Buffers. The active mission buffers, M1 and M2, are used to transmit messages and conduct fire missions. They permit an observer to conduct two simultaneous missions from the DMD, one in cach active mission buffer. Messages must be composed in an active mission buffer or be transferred from an off-line composed message file into an active mission buffer before they can be transmitted.

b. Message Composition in Off-Line Compose Message Files. A message composed in one of the seven off-line compose message files, F3 through F9, may be stored there until transmission is des red. This enables the observer to anticipate future requirements and to prepare messages in advance of their use. Messages stored in the off-line files must be transferred into an active mission buffer before they can be transmitted.

c. Message Structure. A DMD does not transmit messages as they appear to the operator. They are transmitted as a string containing 44 alphanumeric characters. Each DMD message is composed of two parts: the header and the body. The header uses six character positions. The first position of the body designates the message type, and the rest of the body can use up to 37 characters.

    (1) Message Header. The DMD automatically selects the information included in the message header and inserts it into the character positions (Figure B-6).

      (a) The unique address of the destination device is inserted in character position 1. The DMD extracts this alphanumeric character from the DEST field of the status menu.

Figure B-6. DMD MESSAGE HEADER

      (b) When a message is not received by the destination device, it must be retransmitted. The try number indicates the number of times a message has been retransmitted. This number, a numerical value 0 to 3, is automatically inserted into character position 2 of the message header. The try number is used in message authentication.

      (c) An authenticator pair is used in conjunction with the try number to provide message self-authentication. The operator can store a group of authenticator pairs in the authentication code file and cause the DMD to transmit them in order. If the operator has not previously stored authenticator pairs, he may enter them through the keyboard during message composition. In either case, the two alphanumeric characters are inserted into positions 3 and 4 of the message header.

      (d) The entry in position 5 indicates whether the message contains data or is a test message. The DMD extracts this information from the T/D field of the status menu.

      (e) The unique address of the DMD is inserted in character position 6. The DMD extracts this alphanumeric character from the ORIG field of the status menu.

    (2) Message Body. Character position 7, the leading character of the message body, indicates the type of message being transmitted. The remaining 37 characters compose the text of the message. The DMD uses an encoding scheme which automatically converts a composed message into a string of characters. Upon receipt, the destination device decodes the character string and displays the message in a format the operator can read and understand. Each message type uses a different encoding scheme, which is identified by the character in position 7. The entire process of encoding and decoding is not apparent to the DMD operator. It is done automatically by the DMD.

d. Message Flow. When a DMD, FIST DMD, FED, TACFIRE computer, VFMED, or battery computer unit (BCU) receives a digital message, it automatically transmits a brief digital response called an ACK message. The TACFIRE computers can automatically verify message authenticity. When TACFIRE receives a properly self-authenticated message, it transmits an ACK message. When TACFIRE receives an improperly self-authenticated message, it transmits a NAK message. The DMD display shows that an ACK or a NAK message has been received, and the ACK and NAK indicator lamps flash. The operator can clear these indications by pressing the X key. When a NAK has been received, this action causes the AUTH LINE NO field of the status menu to be reset, thereby resynchronizing the DMD with TACFIRE. The other devices cannot automatically verify message authenticity, and they will always transmit an ACK message if a DMD message is received. If neither the ACK nor the NAK light flashes, the destination device did not receive the message.

B-5. AUTHENTICATION

Deception is a form of electronic warfare which might be used against automated FA systems. An enemy force may try to transmit messages which imitate the digital transmissions of legitimate subscribers on the fire direction nets. If TACFIRE or BCS were permitted to process deceptive messages, the enemy could direct artillery fires on friendly positions or input false intelligence information. If FA observers accept deceptive messages as autherltic, the enemy could give them erroneous tactical information or direct them to take improper actions. The authenticity of received messages must be determined to counter the electronic threat. This may be done by using the self-authentication or challenge and response technique.

a. Self-Authentication. Self-authentication is the preferred method of authenticating digital messages, because all required information is transmitted in the message header. Several requirements must be met for this technique to be used. First, the transmitting station must have a current group of authenticators. The DMD operators are issued code books which contain the authenticators they must use. Second, the receiving station must be able to compare the transmitted authentication information with that which should have been transmitted. The DMD destination must, therefore, have a copy of the DMD operator's authenticators. Likewise, the DMD operator must have a copy of the destination codes. Third, the transmitting and receiving stations must be synchronized. Each must know which authenticator pairs have been transmitted and which should be transmitted next. The DMD operator can do this by marking through the codes in the reception code book as messages are received. The DMD can keep track of the codes used for transmission.

    (1) Authenticator Codes. Authenticators are grouped in pairs. Authenticator pairs consist of two alphanumeric characters which are transmitted in a message header. One hundred authenticator pairs form a group, and several groups form a code book. Unit communications security (COMSEC) custodians issue code books to DMD operators. Within a group, each authenticator pair is assigned to a line. The lines are numbered from 01 through 100. The first message transmitted by using the current group must contain the authenticator pair associated with line number 01. Subsequent messages must contain, in order, the authenticators associated with subsequent line numbers. An authenticator pair may be transmitted only once. When a message is composed, the DMD operator must insert the appropriate authenticators into the message header. One of two techniques may be used: retrieval from the authentication code file or input directly from the keyboard.

      (a) Retrieval From the Authentication Code File. An entire group of authenticator pairs may be extracted from a code book and recorded in the DMD authentication code file. Extreme care must be taken to ensure that each authenticator pair is recorded without error. When this is done, the operator must enter an operator's key. The operator key is a unique, easily remembered, alphanumeric pair which the operator selects. The AUTH LINE NO field of the status menu contains the line number of the next authenticator pair to be transmitted. Before any messages are transmitted by using the current group, the value in this field should be 01. When a message is composed, the operator must make an operator's key entry in the AUTH field. When the operator enters the operator's key, the DMD permits continued message composition. When the message is transmitted, the DMD retrieves the authenticator pair stored on the line number specified in the AUTH LINE NO field. That code is transmitted in the message header. The DMD then increments the value in the AUTH LINE NO field by one. If the DMD is synchronized with its destination (the value stored in the AUTH LINE NO field was correct) and if the authenticator pairs have been properly recorded in the file, then the message will be properly self-authenticated. Because the AUTH LINE NO field has been automatically incremented, subsequent messages will also be properly self-authenticated. This technique does not require the operator to manually extract authenticator pairs from his code book each time a message is composed. For this reason, it is the preferred method of message authentication.

      (b) Input Directly From the Keyboard. At times, it may not be possible or desirable to retrieve authenticator pairs from the authentication code file. In these cases, the proper codes are not on file and they must be entered directly from the keyboard. To do this, the DMD operator displays the message AUTH field. He then opens his authentication code book, turns to the current group, and identifies the authenticator pair associated with the next line number to be transmitted. This authenticator pair is entered in the AUTH field. Because the DMD expects the operator key to be entered, an error message will be displayed as follows:

  • *** AUTHENTICATION ERROR

  • *** INCORRECT KEY

      If the operator disregards the error message and reenters the authenticator pair, the DMD accepts the mput and permits continued message composition. The operator should mark through the code in his book to ensute that it is not used again. The authenticator pair that was entered is transmitted in the message header. Because this technique requires the manual extraction of authenticators each time a message is composed, it is not the preferred technique. It can be used effectively, however, when the current group has not been recorded in the authentication code file and a message must be transmitted. It is also useful when the DMD must temporarily transmit to an alternate destination. Directly entered alphanumeric pairs are transmitted in lieu of the stored codes, which will remain unexposed for future use when communicating with the primary destination. Thus, unauthorized personnel (those persons unfamiliar with the operator key) can be kept from transmitting properly authenticated messages using previously stored authenticators.

    (2) Verifying Message Self-Authentication. If a message is transmitted and no ACK or NAK message is received, the operator should assume that the destination did not receive the message and it must be retransmitted. The DMD increments the value of the AUTH LINE NO field of the status menu. Because the destination is unaware of the attempt of the DMD to communicate, it does not increment the line number of the next authenticator pair it expects to receive. This failure to communicate causes the DMD to lose synchronization with its destination. To enable verification of message authenticity under these conditions, a try (retransmission) number is transmitted with the authenticators in the message header. The try number and the authenticators are used together to determine message authenticity.

      (a) Procedure for Verifytng Message Authenticity. Upon receipt of a digital message, the header must be examined to identify the try number and authenticator pair. The try number (a numeric value of 0 to 3) is added to the line number of the next authenticator expected from the originator. The sum is the line number that should correspond to the transmitted authenticator pair. If the transmitted authenticator pair does match the authenticator pair on that line, then the message should be considered authentic. If they do not match, then the authenticity of the message should be questioned. The operator should line through the authenticator pair and any preceding codes which have not been previously marked as having been used.

      (b) Authenticating the First Transmission of a Digital Message. When a message is transmitted for the first time, the try number is 0. The sum of the try number and the next expected line number equals the expected line number. Authentication is done by comparing the transmitted authenticator pair with the one on the expected line.

      (c) Authenticating a Message Retransmission. The DMD will permit three retransmissions before it tells the operator to reestablish voice communication with his destination. When a message is retransmitted, the try number has a value of 1 to 3. Consequently, the sum of the try number and the next expected line number is greater than the expected line number.



EXAMPLE

             A is transmitting to B. They are synchronized.
             An extract of A's current code group is shown.
                 LINE NUMBER             AUTHENTICATOR CODE
                     05                          SG
                     06                          BZ
         A transmits a message to B by using line 05 (try number
         = 0 and authenticator pair = 5G). B does not receive the
         message.
         A retransmits the message by using line 06 (try number
         = 1 and authenticator pair = BZ). B still expects to
         receive the authenticator corresponding to line 05.
         Upon receipt, B adds try number 1 and expected line 05.
         The sum is 06. Because BZ is the authenticator pair
         associated with line 06, the message is properly
         self-authenticated.


b. Challenge and Response Authentication. Normally, a DMD operator is issued one set of authentication code books. These allow him to transmit self-authenticated messages to his primary dejtination. Because of the litnited availability of COMSEC materials, it is unlikely that alternate destinations wiU have a copy. Consequently, it generally is not possible to transmit self-authenticated messages to alternate destinations. Authentication must be done by using the challenge and response technique that is currently used in voice communications. The challenge and response may be transmitted by using FREETEXT messages. It is not practical to authenticate every message in this manner. The DMD operator may be challenged only after his initial transmission and anytime the destination suspects imitative deception. A DMD operator generally communicates with an alternate destination for a limited time. Communications eventually will be reestablished with the primary destination. To prevent exposing the stored authenticator pairs, the DMD operator should enter phony codes by using the direct keyboard input technique. To prevent the loss of synchronization with the primary destination, the DMD operator should note the value stored in the AUTH LINE field of the status menu before destinations are changed. This value must be reentered when communications are reestablished with the primary destination.

B-6. MODE MENU

If the DMD has been properly assembled and power has been applied, the mode menu (Figure B-7) will be displayed. The mode menu is the DMD's main index--the starting point for all DMD operations. It can be displayed anytime by pressing the MODE key. If the mode menu does not appear on the display panel, then adjust the DSP BRT control knob. It may be necessary to press the MODE key to recall the display. If the mode menu still does not appear, take the following corrective actions:

Figure B-7. MODE MENU

  • Check the external power source and external power cable if external power is used.

  • Check the internal battery pack if internal power is used. It may be necessary to replace the battery with one that is fully charged.

  • If the mode menu still is not displayed, evacuate the DMD to the next higher maintenance level.

B-7. PROCEDURE FOR PURGING THE MEMORY

The DMD memory may be purged when it is prepared for use or in emergency situations. This prevents enemy access to the stored information. Purge the memory of the DMD 01. as follows:

  • Display the mode menu by pressing the MODE key.

  • Note the mode menu entry Y = MEMORY PURGE. Purge the memory by pressing the Y key. The entry changes to Y = MEMORY PURGED, indicating successful completion of the operation.

NOTE: For diagnostic test procedures, see subparagraph B-2c above.

B-8. PROCEDURE FOR MAKING INITIAL STATUS SELECTIONS

Establish communications parameters, DMD functional characteristics, and battery conditions by making initial status selections.

a. Display the mode menu by pressing the MODE key.

b. Note the mode menu entry E=STATUS. Press the E key to display the status menu. Entries must be made in all fields with a question mark (?). All other fields except WATT HRS and BATT LMT have default values.

c. Press the JUMP key to display the ORIG field. Enter the unique address of the DMD.

d. DEST is displayed. Enter the unique address of the destination device.

e. T/D is displayed. Select TEST when transmitting test messages; otherwise, select DATA.

f. XMT BLK is displayed. Select DBL when transmitting through heavy radio interference or jamming; otherwise, select SNG. The DMD XMT BLK must match that of the destination.

g. XMT RATE is displayed. Select 600 or 1,200 bits per second in accordance with unit SOP cr communications instructions. The DMD XMT RATE must match that of the destination.

h. PREAMBLE is displayed. Enter a 0.1- to 4.0-second preamble in accordance with unit SOP or communications instructions.

i. AUTH GROUP NO is displayed. Enter the number of the current authenticator group.

j. AUTH LINE NO is displayed. Enter the line number of the next authenticator pair to be transmitted. If no transmission has been made by using the current group, enter 01.

k. DSPL DLY is displayed. Enter the time (0.0 to 2.0 seconds) a menu or message element will remain displayed after an entry or selection has been made

l. KBD BELL VOL is displayed. Set the keyboard bell volume to the desired intensity (0 is completely off, and 7 is the maximum level).

m. MSG BELL VOL is displayed. Set the message bell volume to the desired intensity (0 is completely off, and 7 is the maximum level).

n. WATT HRS is displayed. If a fully charged battery has just been installed or if no internal battery is presently installed, enter 00.0 watt hours; otherwise, press the V key to select the displayed value.

o. BATT LMT is displayed. Enter the number of watt hours that a fully charged battery can be expected to produce. If no battery limit has been determined by experience, enter 12.0.

p. The completed status menu is displayed. Review the status menu and make corrections where appropriate.

B-9. PROCEDURE FOR STORING THE AUTHENTICATION CODE LIST AND OPERATOR'S KEY

An entire group of 100 authenticator pairs and an operator's key may be stored in the authentication code file by using the procedures discussed below.

a. Display the mode menu by pressing the MODE key.

b. Note the mode menu entry F = AUTH CODES. Display the authentication code file instructions by pressing the F key.

c. Enter the line number of the first authenticator pair to be entered. Normally, this will be 01.

d. Press the X key to enter the authentication code file at the line number specified.

CAUTION

Pressing the X key to enter the authentication code file will delete previously used authenticator pairs. The code beginning with the entry line and continuing to (but not including) the line specified in the AUTH LINE NO of the status menu will be erased. When the file is entered, at least one code (on the entry line) will be deleted. Always enter at line 01.

e. Beginning with the entry line and continuing to line 00, extract the authenticator pairs from the current group in the code book, and record them in the authentication code file. Extreme caution must be taken to ensure the codes are stored on the appropriate line and without error.

f. After an entry is made on line 00, select and enter an operator's key. The selected key should be easy to remember. It is used each time a message is composed to cause the DMD to retrieve and transmit the authenticators which have been stored in the file.

B-10. MESSAGE COMPOSITION AND TRANSMISSION

Messages may be composed in active mission buffers, M1 and M2, or in off-line compose message files, F3 through F9. A message can be transmitted only from an active mission buffer. Consequently, a message must be composed in M1 or M2, or it must be transferred from an off-line file into M1 or M2 before it can be transmitted. The paragraphs below discuss composing and transmitting various types of messages.

a. Composing a Message in an Active Mission Buffer and Transmission.

    (1) Display the mode menu by pressing the MODE key.

    (2) Note the mode menu entry 1 = MSN1 ACTV or 2 = MSN2 ACTV. It indicates the mission buffer in which the message will be composed. To activate the other mission buffer, press the 2 or 1 key, as appropriate.

    (3) Note the mode menu entry A = MSG TYPES. Display the message types menu by pressing the A key.

    (4) Note the M1 ACTIVE or M2 ACTIVE entry on the message tvpe menu. This indicates the active mission buffer in which the message will be composed. Select the message to be composed, and display its skeleton by pressing the appropriate alphabetic key.

    (5) Those fields assigned a default value will have the default displayed. Default values will be transmitted il no other selections or entries are made. Those fields with a question mark (?) require an operator entry before transmission is permitted. Some fields, such as DIR or TGT NO, may have previously specified values displayed. These values are drawn from the mission data portion of the active mission buffer.

    (6) The cursor flashes in the AUTH field. Press the JUMP key to display the AUTH field.

    (7) The AUTH field permits, the operator to specify the authenticator pair which will be transmitted in the message header. Either of two techniques may be used.

      (a) Retrieval From the Authentication Code File. If the current group of authenticator pairs has been stored and one of these is to be transmitted, enter the operator's key in the AUTH field. This entry must match the previously stored key in the authentication code file.

      (b) Direct Input From the Keyboard. This technique may be used if the operator has not stored the current group of authenticator pairs. It also may be used if the operator is transmitting to an alternate destination and does not want to expose the previously stored codes. Select the authenticators to be transmitted (not the operator's key), and enter the alphanumeric pair in the AUTH field of the message. This entry will cause an error message to be displayed. Disregard the error message, and reenter the pair.

    (8) Compose the rest of the message. The default or previously specified values may be selected by pressing the down arrow key. When entries have been made in all fields, the completed message is displayed for operator review. To make a correction, move the cursor to the appropriate field, and display it by pressing the JUMP key. Correct the error, and display the corrected message by pressing the JUMP key.

    (9) Listen to the net. If there is no other traffic, transmit the message by pressing the XMIT key.

NOTE: The completed message must be displayed before transmission is permitted.

      (a) If the destination is a TACFIRE computer and it received the message and the authentication was correct or if the destination is a BCS or DMD and it received the message, an ACK message is transmitted back to the DMD. The display and ACK and NAK indicator lamps indicate receipt of the ACK message. The ACK light flashes at twice the speed of the NAK light. Clear the display and turn off the indicator lamps by pressing the X key.

      (b) If the destination is a TACFIRE computer and it received the message and the authentication was incorrect, a NAK message is transmitted back to the DMD. The display and ACK and NAK indicator lamps indicate receipt of the NAK message. The NAK light flashes at twice the speed of the ACK light. The display indicates the line number of the authenticators TACFIRE expected to receive. Clear the display and turn off the indicator lamps by pressing the X key. This action resynchronizes the AUTH LINE NO field of the status menu. Transmit the message again.

      (c) If the destination did not receive the message, no ACK or NAK indications are displayed. The try (retransmission) number is incremented. Transmit the message again.

b. Composing a Message in an Off-Line Compose Message File and Transmission.

    (1) Display the mode menu by pressing the MODE key.

    (2) Note the mode menu entry FILE MSN=#. Select the off-line compose message file, F3 through F9, in which the message is to be composed by pressing the appropriate numeric key. The file number specified replaces the #.

    (3) Note the mode menu entry A=MSG TYPES. Display the message type menu by pressing the A key.

    (4) Note the F# ACTIVE entry on the message type menu. The # indicates the off-line compose message file in which the message will be composed. Select the message to be composed, and display its skeleton by pressing the appropriate alphabetic key.

    (5) Compose the message as described in subparagraphs a(6), (7), and (8) above.

    (6) The message cannot be transmitted from the off-line compose message file. It must be transferred to an active mission buffer. Display the mode menu by pressing the MODE key.

    (7) Note the 1=MSN1 ACTV or 2=MSN2 ACTV entry. This indicates the mission buffer into which the message will be transferred. Note the FILE MSN = # entry. Select the off-line file in which the message was composed. The specified file number replaces #.

    (8) Note the mode menu entry G=ENABLE FILE MSG. Press the G key to transfer the composed message from the selected off-line file into the active mission buffer.

    (9) Transmit the message as described in subparagraph a(9) above.

c. Composing the FR QUICK Message.

    (1) Make an entry in the AUTH field (subparagraph a(7) above).

    (2) Make one of the following entries or selections:

  • Enter a known point number to request fire on a previously recorded known point.

  • Select ASGN KNPT to assign a known point number to a previously recorded target. The target number must be subsequently entered.

  • Select FIRE FPF to command the firing of a previously established final protective fire.

  • Select FIRE TGT NO to request fire on a previously recorded target. The target number must be subsequently entered.

  • Select END FPF to terminate the firing of the FPF.

    (3) Select a LOW or HIGH angle trajectory.

    (4) Assign an URGENT or NORMAL priority to this fire request.

d. Composing the FR GRID Message.

    (1) Make an entry in the AUTH field (subparagraph a(7) above).

    (2) Enter the target location grid coordinates (subparagraph v below).

    (3) Enter the OT direction (to the nearest 10 mils), or select the GT line.

    (4) Enter the target type and description (subparagraph w below).

    (5) Select the desired shell-fuze combination to be fired in effect.

    (6) Select the desired method of control.

    (7) Select a LOW or HIGH angle trajectory.

    (8) Assign an URGENT or NORMAL priority to the fire request. Select FPF (ASSIGN ONLY) to establish an FPF or Copperhead priority mission.

e. Composing the FR SHIFT Message.

    (1) Make an entry in the AUTH field (subparagraph a(7) above).

    (2) Enter the number of the known point from which the target location is determined.

    (3) Enter the OT direction (to the nearest 10 mils).

    (4) Enter the shift information which locates the target with respect to the known point (subparagraph x below).

    (5) Enter the target type and description (subparagraph w below).

    (6) Select the desired shell-fuze combination to be fired in effect.

    (7) Select the desired method of control.

    (8) Select a LOW or HIGH angle trajectory.

    (9) Assign an URGENT or NORMAL priority to the fire request. Select FPF (ASSIGN ONLY) to establish an FPF or Copperhead priority mission.

f. Composing the FR POLAR Message.

    (1) Make an entry in the AUTH field (subparagraph a(7) above).

    (2) Enter the target location polar data (subparagraph w below).

    (3) Enter the target type and description (subparagraph w below).

    (4) Select the desired shell-fuze combination to be fired in effect.

    (5) Select the desired method of control.

    (6) Select a LOW or HIGH angle trajectory.

    (7) Assign an URGENT or NORMAL priority to the fire request. Select FPF (ASSIGN ONLY) to establish an FPF or Copperhead priority mission.

g. Composing the FR LASER Message.

    (1) Make an entry in the AUTH field (subparagraph a(7) above).

    (2) Enter the target location laser polar data (subparagraph z below).

    (3) Specify the type of laser mission to be conducted.

      (a) Select STA TGT to request fire on a stationary target.

      (b) Select PRED PNT to request an FFE fire mission (at the observer's command) on a position to which the observer expects the target to move.

      (c) Select TRAK TGT to request a time on target on a position to which a target is predicted to move. The target must be lased at two locations. The TACFIRE or BCS assumes the target is traveling in a constant direction and at a fixed rate. An engagement point is determined accordingly.

      (d) Select DRAW TGT to describe an irregularly shaped target. The target size and shape may be specified by lasing two to eight locations. DRAW TGT must be specified for each point except the final one, when LAST PNT must be selected.

      (e) Select TRILAT to determine the observer's location (grid coordinates) by using two known points. The FDC must be told (by FREETEXT message) which known points will be lased and which known point is on the observer's left. The leftmost known point must be lased first and identified as PT NO - 1. The rightmost known point must be lased second and identified as PT NO - 2. The BCS then computes the observer's location.

      (f) Select RESECT to determine the observer's location by using one known point. The FDC must be told (by FREETEXT message) which known point will be lased

    (4) Enter the target type and description (for fire requests) (subparagraph w below).

    (5) Select the desired shell-fuze combination to be fired in effect (for fire requests).

    (6) Select the desired method of control (for fire requests).

    (7) Select a LOW or HIGH angle trajectory (for fire requests).

    (8) Assign an URGENT or NORMAL priority to the fire request. Select FPF (ASSIGN ONLY) to establish an FPF or Copperhead priority mission.

h. Composing the SUBQ ADJ Message.

    (1) Make an entry in the AUTH field (subparagraph a(7) above).

    (2) Enter the OT direction (to the nearest 10 mils), or select the GT line. This may be inserted by the DMD.

    (3) If the adjusting round was observed and a shift will be made, select OK. If the adjusting round was not observed, lost, or erratic, select DNO, LOST, or IGN RD, respectively.

    (4) Enter the shift information which adjusts the fire onto the target (subparagraph x below).

    (5) Enter the fire mission target number. This is extracted from the message to observer and may be inserted into the message by the DMD.

    (6) Select the desired shell-fuze combination. Specify NO PREF if no change to the adjusting or FFE munitions is desired.

    (7) Select the desired method of control.

    (8) Select a LOW or HIGH angle trajectory. It should match the trajectory specified in the fire request.

i. Composing the SA LASER Message.

    (1) Make an entry in the AUTH field (subparagraph a(7) above).

    (2) Enter the burst or target location laser polar data (subparagraph z below).

    (3) Specify the status of the adjusting round and which location (burst or target) has been lased as follows:

  • Select OK TGT to identify a new target location.

  • Select OK BT if the adjusting round was observed and the burst location has been lased. The TACFIRE or BCS computes the shift required. Fire for effect can normally be specified after one adjusting round has been observed and lased.

  • Select DNO TGT or LOST TGT if the adjusting round was not observed or was lost and the target location has been lased. This can be used to specify a new target location or the original target location.

  • Select LOST BT if the adjusting round was lost and the estimated burst location has been lased. Because the actual burst location is uncertain, another adjusting round should be requested.

  • Select IGN RD if the adjusting round was erratic and another must be fired.

    (4) Enter the fire mission target number. This is extracted from the MTO and may be inserted into the message by the DMD.

    (5) Select the desired shell-fuze combination. Specify NO PREF if no change to the adjusting or FFE munitions is desired.

    (6) Select the desired method of control.

    (7) Select a LOW or HIGH angle trajectory. It should match the trajectory specified in the fire request.

j. Composing the PREC REG Message.

    (1) Make an entry in the AUTH field (subparagraph a(7) above).

    (2) Enter the OT direction (to the nearest 10 mils), or select the GT line. This may be inserted by the DMD.

    (3) Select the appropriate command as follows:

  • Select N/G if no change to the previously specified command is desired.

  • Select 1 RND, 2 RNDS, or 3 RNDS to command the firing of 1, 2, or 3 rounds, respectively, using the same firing data.

  • Select RCRD REG PT to terminate the impact phase of a precision registration.

  • Select RCRD AS TI REG PT to terminate the time phase of a precision registration.

  • Select REG NEXT LOT in a two-lot registration to terminate the impact or time phases of the first-lot registration and begin registration of the second lot.

    (4) Enter the desired shift information (subparagraph x below).

    (5) Enter the fire mission target number. This is extracted from the MTO and may be inserted into the message by the DMD.

    (6) Select the fuze to be fired. Specify N/G if no change is desired.

    (7) Select the desired method of control.

k. Composing the EOM&SURV Message.

    (1) Make an entry in the AUTH field (subparagraph a(7) above).

    (2) Enter the OT direction (to the nearest 10 mils), or select the GT line. This may be inserted by the DMD.

    (3) Enter the desired refinement (shift) information if the target will be recorded as a known point (subparagraph x below).

    (4) Enter the target type (subparagraph w below). This has been specified in the fire request and may be inserted into the message by the DMD.

    (5) Select the target disposition.

    (6) Enter or select the estimated number of casualties.

    (7) Enter the fire mission target number. This is extracted from the MTO and may be inserted into the message by the DMD.

    (8) Select EOM to end the mission or EOM RAT to end the mission and record the target as a known point.

l. Composing the HB/MPI Message.

    (1) Make an entry in the AUTH field (subparagraph a(7) above).

    (2) Enter the reference direction. This is extracted from the orienting data received from the FDC and may be inserted by the DMD.

    (3) Select the observed error in the burst location as follows:

  • Select RA if the burst location is right of the reference direction and above the reference vertical angle.

  • Select RB if the burst location is right of the reference direction and below the reference veltical angle.

  • Select LA if the burst location is left of the reference direction and above the reference vertical angle.

  • Select LB if the burst location is left of the reference direction and below the reference vertical angle.

    (4) Enter the reference vertical angle. This is extracted from the orienting data received from the FDC and may be inserted by the DMD.

    (5) Enter the number of mils the burst location was right or left of the reference direction.

    (6) Select YES if you have been designated to measure the vertical angle; otherwise, select NO. This is extracted from the orienting data and may be inserted by the DMD.

    (7) If you have been designated to measure the vertical angle, enter the number of mils the burst location was above or below the reference vertical angle; otherwise, select N/G.

    (8) Enter the fire mission target number. This is extracted from the MTO or orienting data and may be inserted by the DMD.

    (9) If the burst was observed, select OK If the burst was not observed, lost, or erratic, select DNO, LOST, or IGN RD, respectively.

    (10) Select HB if observing a high-burst registration or MPI if observing a mean-point-of-impact registration. This is extracted from the orienting data and may be inserted bv the DMD.

m. Composing the RDR REG Message.

    (1) Make an entry in the AUTH field (subparagraph a(7) above).

    (2) Enter the impact location grid coordinates (subparagraph v below).

    (3) If the impact was observed, select OK If the impact was not observed, lost, or erratic, select DNO, LOST, or IGN RD, respectively.

    (4) Enter the fire mission target number. This is extracted from the MTO or orienting data and may be inserted by the DMD.

n. Composing the FO CMD Message.

  • Select FIRE to command the firing of a mission whose control is at the observer's command. The target number must be subsequently entered.

  • Select CHECK FIRE to command the check firing of a specific fire mission. The target number must be subsequently entered.

  • Select CHECK FIRE ALL to command the check firing of all fire missions.

o. Composing the SHELREP Message.

    (1) Make an entry in the AUTH field (subparagraph a(7) above).

    (2) Enter the direction to the location from which the projectiles were fired.

    (3) Enter the impact location grid coordinates (subparagraph v below), omitting altitude.

    (4) Select the type of projectiles.

    (5) Enter the caliber of the projectiles. Select UNK if unknown.

    (6) Enter or select the number of rounds that were fired.

    (7) Enter the time the incident occurred.

p. Composing the FL TRACE Message.

    (1) Make an entry in the AUTH field (subparagraph a(7) above).

    (2) The FLOT is specified by two or more location entries. Enter an entry number and the frontline grid coordinates (subparagraph v below), omitting altitude.

    (3) Enter the entry number for another frontline location, and enter the second frontline location grid coordinates (subparagraph v below), omitting altitude, for the second entry.

    (4) If an observer wishes to send more than two frontline grid coordinates, he must use a second FL TRACE message.

q. Composing the OBSR LOC Message.

    (1) Make an entry in the AUTH field (subparagraph a(7) above).

    (2) Enter the observer location grid cocrdinates (subparagraph v below).

r. Composing the ATI GRID Message.

  • Select N/G if no reliability is specified.

  • Select GOOD, FAIR, or EXC to indicate the reliability of the target acquisition source.

  • Select DNA if the target coordinates are not to be adjusted.

  • Select DNC if the target is not to be combined with another.

s. Composing the FIREPLAN Message.

    (1) Make an entry in the AUTH field (subparagraph a(7) above).

    (2) Enter the names of the FIREPLAN in which this target is to be included.

    (3) Enter the target location grid coordinates (subparagraph v below). The coordinates may be omitted (and N/G selected) if the target has been previously recorded (target number must be entered subsequently).

    (4) Enter the target type and description (subparagraph w below).

    (5) Select CONFIRMD if the target is confirmed or SUSPECTD if the target is suspected.

    (6) Select the accuracy to which the target was located.

t. Message to Observer. Messages to observers are not composed on the DMD. They are transmitted from TACFIRE or BCS and received by the DMD.

u. Composing the FREETEXT Message.

    (1) Make an entry in the AUTH field (subparagraph a(7) above).

    (2) Compose the desired message. It must not exceed 37 characters.

v. Entering Location Grid Coordinates.

    (1) Enter a five-digit easting. In the FR GRID, FL TRACE, and FIREPLAN messages, the last digit is a zero, and the specified easting is accurate to the nearest 10 meters. (2) Enter a five-cligit northing. In the FR GRID, FL TRACE, and FIREPLAN messages, the last digit is a zero, and the specified easting is accurate to the nearest 10 meters.

    (3) Enter a four-digit altitude. In the FR GRID and FIREPLAN messages, the last digit is a zero, and the specified altitude is accurate to the nearest 10 meters. It may be necessary to enter a leading zero.

    (4) In those regions of the world near grid zone boundaries, two grid coordinate systems may be used. Select STD if the standard (westernmost) grid zone coordinates are used; select EST if the easternmost grid zone coordinates are used. If the location is not near a grid zone boundary, select STD.

w. Entering Target Type and Description.

    (1) Select the target type and subtype. If N/G is selected, TACFIRE and BCS will assume a personnel target.

    (2) Enter the number of elements in the target.

    (3) For personnel targets, select their degree of protection. For other target types, select N/G.

    (4) Select the target radius or length. If N/G is selected, TACFIRE and BCS will assume a circular target with a 100-meter radius.

    (5) For rectangular targets, select the target width. For circular targets, select N/G.

    (6) For rectangular targets, enter the target attitude.

x. Entering Shift Information.

    (1) Select the direction of the desired lateral shift. The magnitude of the lateral shift must be entered subsequently. If no lateral shift is desired, select N/G.

    (2) Select the direction of the desired range shift. The magnitude of the range shift must be entered subsequently. If no range shift is desired, select N/G.

    (3) Select the direction of the desired vertical shift. The magnitude of the vertical shift must be entered subsequently. If no vertical shift is desired, select N/G.

y. Entering Target Location Polar Coordinates.

    (1) Enter the OT direction.

    (2) Enter the OT horizontal distance.

    (3) Select the direction of the desired vertical shift. The magnitude of the vertical shift must be entered subsequently. If no vertical shift is desired, select N/G.

z. Entering Target Location Laser Polar Coordinates.

    (1) Enter the OT direction.

    (2) Enter the OT slant distance.

    (3) Select the direction, and enter the magnitude of the vertical angle.

NOTE: This information can be transferred across the DMD-G/VLLD interface and entered automatically when the target is lased. Section II.

Section II

FORWARD ENTRY DEVICE

B-11. OPERATION OF FORWARD ENTRY DEVICE CP-1995/U

a. Description. The forward entry device (FED) is a lightweight, hand-held communications message processor. It can compose, transmit, receive, edit, store, and display messages to conduct fire support. Messages that it transmits and receives include requests for fire, artillery target intelligence messages, messages to observers, plaintext messages, observer locations, registrations, fire plans, and the forward line of own troops (FLOT). The FED performs polar-to-grid conversions, calculates the observer's position location, and interfaces with the G/VLLD to process laser missions. The message processor performs the tasks of message composition, editing, address coding, error control checking, and net protocol. The operator can specify message data rates, addresses of receiving agencies, and keying times. The FED can transfer its software to another FED. The FED can be programmed either to function as a FIST FED or for use by an observer. The FED is shown in Figure B-8.

b. Data Entry and Display. Information is entered into the FED by use of a keyboard consisting of 64 alphanumeric, symbol, and function keys. The display screen can display 25 lines of text with 40 characters per line.

c. Memory Capacity. With the FED, an observer can store nine active messages at one time, including two fire missions. The FED can hold 40 messages in the received buffer and can store 10 messages in the save buffer. The FED also stores copies of the last 25 messages transmitted.

d. Communications. The FED communicates either over radio by use of a CX-8830 cable or over wire. It gives the observer a single-channel digital capability with point-to-point and netted (multiple subscriber) communications.

e. Authentication. Authentication procedures with a FED are similar to those with a DMD. The FED can store up to four authentication code tables of 100 authenticator pairs each as well as an authentication key code.

f. Power Supply. The FED is powered either by an internal battery (BA-5800 lithium battery) or by 28 volts DC using a DCA-11 DC adapter with a CX-8835 cable.

B-12. FORWARD ENTRY DEVICE MESSAGE FORMATS

The FED communicates with other digital devices by using 25 fixed-format message types. These types are divided into the six categories discussed below.

a. Standard Fire Requests. FED-equipped observers use seven standard fire request messages to conduct fire missions.

Figure B-8. FORWARD ENTRY DEVICE

    (1) FR QUICK (Fire Request, Quick Response). The FR QUICK message is used to request that TACFIRE or BCS assign a known point number to a previouily stored target, to fire an FPF, to terminate firing an FPF, and to request fire on a known point or target that is stored in TACFIRE or BCS.

    (2) FR GRID (Fire Request, Grid Coordinates). The FR GRID message is used to request fire by using the grid coordinates method of target location.

    (3) FR SHIFT (Fire Request, Shift From a Known Point). The FR SHIFT message is used to request fire by using the shift from a known point method of target location.

    (4) FR POLAR (Fire Request, Polar Coordinates). The FR POLAR message is used to request fire by using the polar coordinates method of target location.

    (5) FR LASER (Fire Request, Laser, Polar Coordinates). The FR LASER message is used to request fire by using the laser polar coordinates method of target location. Interface with the G/VLLD enables data to be transferred directly from the G/VLLD into the FR LASER message.

    (6) FR MOV1 (Fire Request, Moving Target, One Point). The FR MOV1 message is used to request fire on a moving target by using one set of grid coordinates.

    (7) FR MOV2 (Fire Request, Moving Target, Two Points). The FR MOV2 message is used to request fire on a moving target by using two sets of grid coordinates.

b. Adjustment Messages. The four adjustment messages are used to make necessary corrections for previously requested missions.

    (1) SUBQ ADJ (Subsequent Adjustment). The SUBQ ADJ message is used to adjust fires onto a target when an FR SHIFT or FR POLAR message has been used in the initial request for fire.

    (2) SA COORD (Subsequent Adjustment, Grid Coordinates). The SA COORD message is used to adjust fires onto a target when an FR GRID message has been used in the initial request for fire.

    (3) SA LASER (Subsequent Adjustment, Laser). The SA LASER message is used to adjust fires onto a target when an FR LASER message has been used in the initial request for fire.

    (4) EOM&SURV (End of Mission and Surveillance). The EOM&SURV message permits the observer to end a fire mission, make refinements, report target surveillance, and request that a target be recorded.

c. Registration Messages. The three registration messages are used in observing precision, HB or MPI, and radar registrations.

    (1) PREC REG (Precision Registration). The PREC REG message is used to adjust the firing of a precision registration or a destruction mission.

    (2) HB/MPI (High Burst or Mean Point of Impact). The HB/MPI message is used to report spottings made in observing an HB or MPI registration.

    (3) RDR REG (Radar Registration). The RDR REG message is used by a radar section to report the impact grid coordinates of rounds fired in a radar registration.

d. Intelligence Messages. The three intelligence messages are used to report information of intelligence value.

    (1) ATI GRID (Artillery Target lntelligence, Grid Coordinates). The ATI GRID message is used to report enemy locations by use of grid coordinates.

    (2) ATI POLAR (Artillery Target Intelligence, Polar Coordinates). The ATI POLAR message is used to report enemy locations by use of polar coordinates.

    (3) SHELREP (Shelling Report). The SHELREP message is used to report information concerning the impact of enemy artillery or mortar fire.

e. Information Messages. The seven information messages are used to send and receive various important information.

    (1) FIRE PLAN (Planned Fire Mission). The FIRE PLAN message is used to establish a planned fire mission.

    (2) FL TRACE (Frontline Trace). The FL TRACE message is used to report the front line of troops of the observer's associated maneuver element.

    (3) FM ALERT (Fire Mission Alert). The FM ALERT message is used to alert the FDC or another subscriber about a fire mission.

    (4) FO CMD (Forward Observer Command). The FO CMD message is used to fire a mission established at the observer's command and to order check firing. The FDC uses this message to report SHOT, SPLASH, and READY to the observer.

    (5) MTO (Message to Observer). The MTO is used by the FDC to report fire mission data to the observer.

    (6) OBSR, OC (Observer Location). The OBSR LOC message is used to report the observer's location to the FIST or FDC. The FDC uses this message to report the observer's location to the observer when that location is determined by resection or trilateration.

    (7) FREETEXT (Plaintext). The FREETEXT message is used for nonformatted messages.

f. Remote Loop Test. The remote loop test (LOP TEST) message is used to conduct a test of the communications link between digital subscribers. The loop test interval is established during initialization. Under normal operations, a warning message is received if the loop test fails.

B-13. MESSAGE TRANSFER MODES

The FIST's FED can be programmed to function in one of three message transfer modes for each observer.

a. Review Mode. All message traffic from an observer's FED is addressed to the FIST's FED. The message must be called up, modified if desired, and then retransmitted to the subscriber selected by the FIST.

b. Automatic Mode. A link is established between two subscribers of the FIST's FED A message addressed to the FIST's FED for another subscriber is automatically readdressed and transmitted to the receiving subscriber. No action by the FIST is necessary when the automatic mode has been programmed for two subscribers.

c. Fire Request Approval Mode. A link is established between an observer and a fire support asset. The initial request for fire is actioned by the FIST as in the review mode. A link is then established, and subsequent messages between the observer and the fire support asset are transmitted as in the automatic mode.

B-14. PREPARATION FOR USE

Before use, the FED must be prepared as discussed below.

a. Power Source Installation. Take the following steps to install the power source:

  • Turn the POWER switch to OFF.

  • Remove the battery compartment cap.

  • Install either a BA-5800/U battery or a DCA-11 DC adapter.

b. Communications Interface.

    (1) Radio. Remove the cap from the communications (comm) port, and connect the CX-8830 cable to the FED comm port and to a radio receptacle.

    (2) Wire. Strip one-half inch of insulation from the ends of the wire line, and insert them into the FED binding posts.

c. Operational Checks. Take the following steps to ensure proper operation of the FED:

  • Turn the POWER switch to ON. The FED will show a self-test prompt. The self-test can be bypassed by pressing the SPACE key.

  • If the main menu is displayed, press the 1 key and the ENTER key.

  • Adjust the DIM and CONT knobs.

  • Press the MODE key.

  • Display OPERATIONAL SERVICE from the mode menu.

  • Display the diagnostics menu. Select and perform diagnostic checks as needed.

  • Press the MAP (F5) key to quit diagnostics.

  • Press the 1 key and the ENTER key to return to the FED program.

d. Initialization. The following steps explain how to establish the FED status, net status, subscriber (member) data, and authentication table:

  • Display FED STATUS from the mode menu.

  • Enter FED status data in the following fields:

    -- NXT TARGET NO.

    -- TIME SET.

    -- LOP TEST.

    -- OBSERVER.

    -- LOCAL ADDRESS.

    -- FED ADDRESS.

    -- KEY BELL VOLUME.

    -- MSG BELL VOLUME.

    -- DISPLAY DELAY.

    -- TEST DATA.

  • Enter location data in the following fields:

    -- EASTING.

    -- NORTHING.

    -- ALTITUDE.

    -- GRID ZONE.

NOTE: If self-location is to be used, go to subparagraph e below.

  • If equipped with a G/VLLD, enter data in the following fields:

    -- CPH TIMER MOD.

    -- CLOUD HEIGHT.

    -- G/VLLD CODE.

    -- VISIBILITY CODE.

  • Display NET STATUS from the mode menu.

  • Enter the net status data in the following fields:

    -- BLOCK.

    -- PREAMBLE.

    -- RATE.

    -- DELAY.

    -- CONNECTION.

    -- SQUELCH.

  • Display MEMBER DATA SUMMARY from the mode menu.

  • Enter the member's address and member data in the following fields for up to 14 members:

    -- TYPE.

    -- ROUTING.

    -- UNIT.

    -- EASTING.

    -- NORTHING.

    -- ALTITUDE.

    -- GRID ZONE.

    -- CLOUD HEIGHT.

    -- G/VLLD CODE.

    -- VISIBILITY CODE.

    -- DEVICE TYPE.

    -- ROUTING MODE.

    -- OBSERVER.

NOTE: Cloud height, G/VLLD code, and visibility code are laser data for an FO with a laser device.

  • Display MEMBER MONITOR from the mode menu.

  • Enter member monitor data consisting of addresses for each member and message groups to be monitored.

  • Display AUTHENTICATION TABLE SUMMARY from the mode menu.

  • Enter authentication data consisting of member addresses, group numbers, line numbers, authenticator pairs, and an operator's key code.

  • Press the X key to enable the authentication table.

e. Self-Location. Calculate the FED self-location as follows:

    (1) Display FED STATUS from the mode menu.

    (2) Display SURVEY MODE METHODS. The observer uses one of four methods in calculating FED self-location.

      (a) Laser One-Point Method. The following are steps in calculating self-location by the laser one-point method:

  • Select LASER ONE POINT METHOD.

  • Enter data in the EASTING, NORTHING, ALTITUDE, and GRID ZONE fields.

  • Designate the known point.

  • Enter data in the DIRECTION, VERT ANGLE, and SLANT DIST fields.

  • Press the C key. The FED location is displayed.

      (b) Laser Two-Point Method. The following are steps in calculating self-location by the laser two-point method:

  • Select LASER TWO POINT METHOD

  • Enter data in the EASTING, NORTHING, and ALTITUDE fields for the left known point.

  • Designate the left known point.

  • Enter data in the DIRECTION, VERT ANGLE, and SLANT DIST fields for the left known point.

  • Repeat the preceding three steps for the right known point.

  • Enter data in the GRID ZONE field.

  • Press the C key. The FED location is displayed.

      (c) Manual Direction Method. The following are steps in calculating self-location by the manual direction method:

  • Select MANUAL DIRECTION METHOD.

  • Enter data in the EASTING, NORTHING, and DIRECTION fields for the left known point.

  • Enter data in the EASTING, NORTHING, and DIRECtION fields for the right known point.

  • Enter data in the GRID ZONE field.

  • Press the C key. The FED location is displayed.

      (d) Manual Distance Method. The following are steps in calculating self-location by the manual distance method:

  • Select MANUAL DISTANCE METHOD.

  • Enter data in the EASTING, NORTHING, and DISTANCE fields for the left known point.

  • Enter data in the EASTING, NORTHING, and DISTANCE fields for the right known point

  • Enter data in the GRID ZONE field.

  • Press the C key. The FED location is displayed.

B-15. POWER OR COMMUNICATIONS FAILURE

In case of power or communications failure, certain steps must be taken to restore the FED to operation.

WARNING
Before reestablishing power, always turn the POWER switch to OFF.

a. Battery Power. The following are steps for restoring battery power:

  • Replace the BA-5800/U battery.

  • Turn the POWER switch to ON and wait 60 seconds. If FED POWER UP does not appear on the display screen, change to an alternate power source or send the FED to maintenance.

b. External Power. The following are steps for restoring power from an external source:

  • Check the CX-8835 cable for damaged or loose connections. If it is damaged, replace it with an undamaged cable or change to internal battery power.

  • Remove the CX-8835 cable, and remove the DCA-11 DC adapter from the cable.

  • Check the adapter for damage. If it is damaged, insert another adapter and replace the CX-8835 cable.

  • Turn the POWER switch to ON and wait 60 seconds. If FED POWER UP does not appear on the display screen, change to alternate power source or send the FED to maintenance.

c. Communications Failure. The following are steps for restoring communications:

  • If a "no acknowledgement" is received, the FED will try to transmit the message three additional times.

  • If attempts are unsuccessful, contact the subscriber by alternate means.

  • Determine if incorrect net status data is the reason for failure. Correct net status data and try message transmission again.

  • If still unable to communicate and if using wire, check the binding posts for loose connections and the wire for breaks. Repair and replace wire as necessary.

  • If still unable to communicate and if using radio, troubleshoot the radio IAW appropriate technical publications. If troubleshooting is unsuccessful, replace the radio.

  • After problems have been corrected, display MESSAGE TYPES from the mode menu.

  • Display FREETEXT message, and enter data in the AUTH, DEST, and TEXT fields.

  • Transmit the FREETEXT message. If digital communication is unsuccessful, send the FED to maintenance.

B-16. SAVE OR PURGE DATA AND POWER DOWN

The following paragraphs cover how to save or purge all operational data, how to power down the FED, and how to disconnect the communications and power sources.

a. Save Data. The following are steps to save data:

  • Display the mode menu.

  • Press the S key. DATA BASE SAVE COMPLETE should appear on the screen.

  • Turn the POWER switch to OFF.

b. Purge Data. The following are steps 10 purge operational data:

  • Display the mode menu.

  • Press the Z key, and turn the POWER switch to OFF.

c. Disconnect Power Source. Remove either the BA-5800/U battery or the DCA-11 DC adapter from the FED.

d. Disconnect Communications Equipment. Remove the CX-8830 cable if using a radio. If using wire, remove the wire.

B-17. UP-LOAD AND DOWN-LOAD THE CURRENT FORWARD ENTRY DEVICE SOFTWARE

The following paragraphs provide information on how to connect a host FED to a target FED and how to transfer current software data from the host FED to the target FED.

a. Connect a host FED to a target FED by using a CX-8834 cable.

b. If the target FED has no software, initialize it as follows:

  • Turn the POWER switch to ON. The main menu should be displayed.

  • Display the setup menu.

  • Display DATE CHANGE, and enter the current date.

  • Display TIME CHANGE, and enter the current time.

  • Display DISK VOLUME, and enter 016 for the random-access memory (RAM) disk volume.

c. If the target FED has software, down-load the host FED current software as follows:

  • Turn the POWER switch to ON.

  • Display the main menu from OPERATIONAL SERVICE.

  • Display UPLOAD/DOWNLOAD.

  • Display PERIPHERAL DEVICE INTERFACE from CHANNEL SET UP.

  • Enter and save setup data. (Ensure data rate is 56000.)

  • Display SEND FILE.

  • Enter drive name C:/ and file name FED.FL; then start file transfer.

d. Up-load at the target FED as follows:

  • Turn the POWER switch to ON.

  • Display the main menu from OPERATIONAL SERVICE (only at target FED with software).

  • Display UPLOAD/DOWNLOAD.

  • Display PERIPHERAL DEVICE INTERFACE from CHANNEL SET UP.

  • Enter and save set-up data. (Ensure data rate is 56000.)

  • Display GET FILE.

  • Enter drive name C:/ and file name FED.FL; then start file transfer.

  • Repeat the procedures to down-load the host FED and down-load the target FED, as shown above, to up-load file FED.EXE by using drive C:\HTUAPP.

e. Return the host and target FEDs to mode menu as follows:

  • Display MAIN MENU.

  • Select the option to load applications program.

  • Press the MODE key.

f. Complete the up-load and down-load of software as follows:

  • Disconnect the host FED from the target FED.

  • Turn the POWER switch to OFF on both FEDs.

  • Remove the CX-8834 cable from both FEDs.

B-18. MESSAGE PROCESSING PROCEDURES

a. Processing Messages in the Received or Saved Message Queues or the Message Copies File. This paragraph covers procedures on how to display a message from the received or saved message queue and from the message copies file, how to edit and transmit a message from the received or saved message queue, and how to save or delete a message in the received or saved message queue.

    (1) Display a message from the received or saved message queue as follows:

  • Press the MSG key to display a received message.

  • Press the SAVE key to display a saved message.

    (2) Display a message from the message copies file as follows:

  • Press the MODE key.

  • Select MESSAGE COPIES; then select the desired message.

NOTE: Messages from the MESSAGE COPIES file can only be displayed.

    (3) Edit and transmit a message in the received or saved message queue as follows:

  • Display and edit the selected fields.

  • Transmit the message. The status line should display an ACK.

    (4) Save a message in the received or saved message queue as follows:

  • Select the message to be saved.

  • Press the S key.

    (5) Delete a message in the received or saved message queue as follows:

  • Select the message to be deleted.

  • Press the D key.

b. Moving and Copying Messages in the Local Files.

    (1) Move a message in the local files as follows:

  • Display LOCAL FILES from the mode menu.

  • Select the message to be moved.

  • Press the D key,

  • Select the file to which the message will move,

    (2) Copy a message in local files as follows:

  • Display LOCAL FILES from the mode menu,

  • Select the message to be copied.

  • Press the E key.

  • Select the file to which the message will be copied,

c. Processing Information Messages. Proces information messages as follows:

  • Select MESSAGE TYPES from the mode menu.

  • Select the desired message format; complete and review the message.

  • Transmit the message, ACK should appear in the status line.

d. Processing Mission Data in the Mission Data Files. The following are procedures to display mission data from the active mission list or member data summary and to edit or delete a mission data record:

  • Display ACTIVE MISSION LIST or MEMBER DATA SUMMARY from the mode menu.

  • Select the mission data record from ACTIVE, MISSION LIST or MEMBER DATA SUMMARY.

  • Edit mission data as follows:

    -- Enter changes to data in selected fields of the displayed MISSION DATA record. The fire request or last mission message can be edited whil viewing the MISSION DATA display. Editing the fire request updates the last mission message and the original fire request.

    -- Redisplay the ACTIVE MISSION LIST or MEMBER DATA SUMMARY.

  • Delete the mission data record by pressing the D key. ACTIVE MISSION LIST or MEMBER DATA SUMMARY will appear on the screen.

e. Processing Local Known Points.

    (1) Create a local known point as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Display the FR GRID message.

  • Enter data as required, including SPC EOM RAT in the CONTROL field.

  • Press the XMIT key. The status line will not appear.

    (2) Delete a local known point as follows:

  • Display LOCAL KNOWN POINTS from the mode menu.

  • Select the local known point to be deleted and press the D key.

f. Processing Recorded Targets.

    (1) Create a recorded target as follows:

  • Display RECORDED TARGETS from the mode menu.

  • Display the next blank RECORDED TARGET DATA display.

  • Enter data as required,

    (2) Display a recorded target as follows:

  • Display RECORDED TARGETS from the mode menu.

  • Select the recorded target record.

    (3) Edit a recorded target as follows:

  • Enter changed data in fields to be updated.

  • Display RECORDED TARGETS file.

    (4) Delete a recorded target as follows:

  • Select the recorded target record.

  • Press the D key to delete the record.

  • Press the Y key. A FREETEXT message is shown addressed to the subscriber that created the recorded target.

  • Transmit the FREETEXT message. ACK should appear in the status line.

B-19. FIRE MISSION PROCESSING PROCEDURES

a. Area Fire Mission Procedures.

    (1) Initiate an area fire mission as follows:

  • Display MESSAGE TYPES trom the mode menu.

  • Display the fire request message. The FR GRID, FR SHIFT, FR POLAR, or FR LASER format is used to initiate an area fire mission.

  • Enter data as required.

  • Transmit the fire request to the FDC. ACK should appear in the status line.

  • Display the MTO, FO CMD:SHOT, and FO CMD:SPLASH messages in sequence as received.

    (2) Process subsequent adjustments as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Display the subsequent adjustment message. The SUBQ ADJ, SA COORD, or SA LASER format is used to process a subsequent adjustment.

  • Enter refinement data for each subsequent observed round.

  • Transmit the subsequent adjustment message. ACK should appear in the status line.

    (3) End the fire mission as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Display the EOM&SURV message.

  • Enter final refinement and surveillance data and either EOM or EOM RAT.

  • Transmit the EOM&SURV message. ACK should appear in the status line.

  • Display the received MTO if a recorded target will be created.

b. Precision Registration Mission Procedures. The FDC initiates the precision registration mission by requesting the observer's direction to a target specified by the FDC or selected by the observer.

    (1) Initiate a precision registration mission as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Display the FR GRID message.

  • Enter data as required, including REG AF or AMC REG in the CONTROL field.

  • Transmit the message to the FDC. ACK should appear in the status line.

  • Display the MTO, FO CMD:SHOT, and FO CMD:SPLASH messages in sequence as received.

    (2) Process subsequent adjustments as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Enter data as required.

  • Transmit the message. ACK should appear in the status line.

  • Display the FO CMD:SHOT and FO CMD:SPLASH messages in sequence as received.

    (3) End the impact phase of the precision registration as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Display the PREC REG message.

  • Enter data as required, including RCRD REG PT in the COMMAND field. Enter TlME RPT in the FUZE field if a time phase is to be conducted.

  • Transmit the message. ACK should appear in the status line.

  • Display the FO CMD:SHOT and FO CMD:SPLASH messages in sequence as received.

    (4) Conduct the time phase of the precision registration as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Display the PREC REG message.

  • Enter data as required.

  • Transmit the message. ACK should appear in the status line.

  • Display the FO CMD:SHOT and FO CMD:SPLASH messages in sequence as received.

    (5) End the time phase of the precision registration as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Display the PREC REG message.

  • Enter data as required, including RCRD AS TI REG PT in the COMMAND field and EOM in the CONTROL field.

  • Transmit the message. ACK should appear in the status line.

c. High Burst/Mean-Point-of-lmpact Registration Mission Procedures.

    (1) Initiate an HB or MPI registration mission as follows:

  • Display the received HB/MPI message.

  • Display MESSAGE TYPES from the mode menu.

  • Display the FREETEXT message.

  • Enter READY TO OBSERVE in the FREETEXT message.

  • Transmit the FREETEXT message to the FDC. ACK should appear in the status line.

  • Display the FO CMD:READY, FO CMD:SHOT, and FO CMD:SPLASH messages in sequence as received.

    (2) Process subsequent adjustments as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Display the HB/MPI message.

  • Enter data as required, including OBSERVED ERROR and DIRECTION ERROR, and VERT ANGLE ERROR if required to report vertical angle spotting.

  • Transmit HB/MPI message. ACK should appear in the status line.

  • Display the received FO CMD:SHOT message.

    (3) To end the HB/MPI mission, the FDC sends a FREETEXT message when it has sufficient data. End the mission as follows:

  • Display the received FREETEXT message.

  • Display the LOCAL FILES from the mode menu.

  • Delete the HB, MPI mission.

d. Copperhead Mission Procedures.

    (1) Initiate the Copperhead mission as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Display the fire request message. The FR GRID, FR POLAR, or FR LASER format is used to initiate a Copperhead mission.

  • Enter data as required. If a priority target, CONTROL is DNL and PRIORlTY is ASGN FPF. If a target of opportunity, CONTROL is AMC/FFE and PRIORlTY is URGENT.

  • Transmit the message to the FDC. ACK should appear in the status line.

    (2) Issue the command to fire as follows:

  • Display the received MTO.

  • Display the received FO CMD:READY (target of opportunity) or the MTO from MISSION DATA through the local files (priority target).

  • Prepare the FO CMD:FIRE message (target of opportunity).

  • Transmit the FO CMD:FIRE message. ACK should appear in the status line. (Target of opportunity procedures for issuing the command to fire end here.)

  • Prepare the FR QUICK message (priority target).

  • Store the FR QUICK message in an off-line file of the local files (priority target). Other functions can be performed until it is time to execute the priority fire mission.

  • Select the stored FR QUICK message from the local files (priority target).

  • Move the FR QUICK message to file 1 or 2 (priority target).

  • Transmit the message. ACK should appear in the status line. (Priority target procedures for issuing the command to fire end here.)

    (3) Execute the Copperhead mission as follows:

  • The observer should receive an FO CMD:SHOT message within 15 to 20 seconds. When that message is received, the counter starts automatically. If the FO CMD is not received, press the S key to start the counter.

  • When the counter reaches 20 ceconds, **DESIGNATE** will appear on the screen. Designate the target until all rounds have impacted. When multiple rounds are fired, the FDC will transmit FO CMD:RNDS COMP after all rounds have been fired.

    (4) Delete the Copperhead mission as follows

  • Display MESSAGE TYPES from the mode menu.

  • Display the EOM&SURV message format (target of opportunity) or the FR QUICK message format (priority target).

  • Enter data as required, including EOM in the CONTROL field (target of opportunity) or DELETE in the KNOWN POINT field (priority target).

  • Transmit the message. ACK should appear in the status line.

e. Final Protective Fire (FPF) Mission Procedures. The following procedures detail how to conduct a center point or a laser draw FPF mission.

    (1) Initiate the FPF mission as follows:

NOTE: When conducting a laser draw mission, the automatic target numbering capability must be turned off first.

  • Display MESSAGE TYPES from the mode menu.

  • Display the fire request message. To initiate an FPF, use the FR GRID, FR LASER, FR POLAR, or FR SHIFT format.

  • Enter data as required. If conducting a laser draw mission, MISSION is DRAW TGT, CONTROL is FFE, and PRIORITY is ASGN FPF. If conducting a center point mission, CONTROL is DC AF and PRIORITY is ASGN FPF.

  • Transmit the message. ACK should appeal in the status line.

NOTE: If conducting a laser draw mission, transmit an FR LASER message for each aimpoint requested by the FDC. For the last aimpoint transmitted MISSION is LAST PNT.
  • Display the MTO, FO CMD:SHOT, and FO CMD:SPLASH messages in sequence as received.

    (2) Process subsequent adjustments as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Display the subsequent adjustment message. If conducting a laser draw mission, use SA LASER. If conducting a center point mission, use SUBQ ADJ or SA LASER.

  • Enter data as required, including DC AF in the CONTROL field.

  • Transmit the SUBQ ADJ or SA LASER message. ACK should appear in the status line.

NOTE: The preceding procedures for subsequent adjustments are followed until the adjustment phase is completed.

    (3) End the adjustment phase of the FPF as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Display the EOM&SURV message.

  • Enter data as required, including EOM or EOM RAT in the CONTROL field.

  • Transmit the EOM&SURV message. ACK should appear in the status line. If the location will not be recorded as a target, the end of adjustment phase is complete.

  • Display the MTO message received from the FDC.

    (4) Execute the FPF as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Display the FR QUICK message.

  • Enter data as required, including FIRE FPF in the KNOWN POINT field.

  • Transmit the FR QUICK message. ACK should appear in the status line.

  • Display the FO CMD:SHOT and FO CMD:SPLASH messages in sequence as received.

    (5) End the FPF as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Display the FR QUICK message.

  • Enter data as required, including END FPF in the KNOWN POINT field.

  • Transmit the FR QUICK message. ACK should appear in the status line.

  • Display the received FO CMD:SHOT message.

NOTE: To save an FPF in the off-line file for reexecution later, follow the procedures in subparagraph B-18b above.

    (6) Delete the FPF as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Display the FR QUICK message.

  • Enter data as required, including DELETE in the KNOWN POINT field.

  • Transmit the FR QUICK message. ACK should appear in the status line.

f. Moving Target Mission Procedures.

    (1) Initiate a moving target mission as follows:

      (a) Display MESSAGE TYPES from the mode menu.

      (b) Display FR MOV1 or FR MOV2 message.

      (c) Enter data as required, including PRTY FS in the PRIORITY field.

      (d) Transmit FR MOV1 or FR MOV2 message to the FDC. ACK should appear in the status line.

      (e) Display MTO received from the FDC.

NOTE: If the following messages are received, go to the
subparagraphs indicated and continue the procedures:
FO CMD:UPDTGT.... f(1)(f)
Accurate FO CMD:PREDPT--not under check fire.... f(1)(i)
Inaccutate FO CMD:PREDPT... f(1)(j)
Accurate FO CMD:PREDPT--under check fire.... f(1)(o)

      (f) Form FR MOV1 or FR MOV2 message.

      (g) Enter updated information as required.

      (h) Transmit FR MOV1 or FR MOV2 message. ACK should appear in the status line.

NOTE: Go to subparagraph f(1)(f) to process the next FO CMD.

      (i) Press the PREV key.

      (j) Form the FO CMD:CHECK FIRE message.

      (k) Transmit the FO CMD:CHECK FIRE message. ACK should appear in the status line.

      (l) Form the last FR MOV1 or FR MOV2 message.

      (m) Enter updated information as required.

      (n) Transmit the FR MOV1 or FR MOV2 message. ACK should appear in the status line.

NOTE: Go to subparagraph f(1)(f) to process the next FO CMD.

      (o) Press the PREV key.

      (p) Display MESSAGE TYPES from the mode menu.

      (q) Display the FO CMD message.

      (r) Enter data as required, including CANCFR in the MISSION INFO field.

      (s) Transmit the FO CMD message. ACK should appear in the status line.

    (2) Delete a moving target mission as follows:

  • Display local files from the mode menu.

  • Display MISSION DATA for the moving target mission.

  • Press the D key to delete the mission.

g. Immediate Suppression Mission Procedures.

    (1) Initiate an immediate suppression mission as follows:

      (a) Press the FIRE MISSION (F6) key.

NOTE: If FR GRID is displayed, go to subparagraph g(1)(d). If LOCAL FILES is displayed with a warning, go to subparagraph g(1)(b).

      (b) Select MESSAGE TYPES.

      (c) Display the FR GRID message.

      (d) Enter data as required, including FFE in the CONTROL field and URGENT in the PRIORITY field.

      (e) Transmit the fire request to the FDC. ACK should appear in the status line.

      (f) Display the MTO, FO CMD:SHOT, and FO CMD:SPLASH messages in sequence as received.

    (2) Process subsequent adjustments as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Display the SUBQ ADJ message.

  • Enter required refinement and surveillance data for each subsequent observed round, including RFFE in the CONTROL field.

  • Transmit subsequent adjustment message. ACK should appear in the status line.

    (3) End the fire mission as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Display the EOM&SURV message.

  • Enter final refinement and surveillance data and either EOM or EOM RAT.

  • Transmit the EOM&SURV message. ACK should appear in the status line.

  • Display the received MTO if a recorded target is to be created.

B-20. CHECK FIRE AND CANCEL CHECK FIRE PROCEDURES

a. Check fire a fire mission as follows:

  • Display MESSAGE TYPES firom the mode menu.

  • Display the FO CMD message.

  • Enter data as required.

  • Transmit the message. ACK should appear in the status line.

b. Cancel check fire on a mission as follows:

  • Display MESSAGE TYPES from the mode menu.

  • Display the FO CMD message.

  • Enter data as required.

  • Transmit the message. ACK should appear in the status line.

Section III

FIST DIGITAL MESSAGE DEVICE

B-21. OPERATION OF THE FIST DMD (AN/PSG-5)

The FIST DMD (Figure B-9) has three major functions:

  • Reduce the number of subscribers handled by the TACFIRE computer.

  • Provide internet communications.

  • Coordinate local company FSO resources.

a. Use of the FIST DMD reduces the number of TACFIRE computer subscribers. All communicating resources assigned to a FIST normally communicate only with the FIST DMD. All forward observer-TACFIRE communications can be controlled by the FIST DMD. The company FSO decides which information must be forwarded to TACFIRE.

b. Instead of each FO communicating directly with TACFIRE, all FOs assigned to a FIST normally communicate only with the FIST DMD. The company FSO has control in deciding the destination of information from each subscriber. Two obvious benefits from this system are:

  • The elimination of duplicate targets before they reach TACFIRE.

  • The elimination of targets from TACFIRE that can be accommodated by the local FIST resources, such as the company and battalion mortars.

The net effect of these changes is to reduce the number of messages handled by TACFIRE, thus improving reaction time of the system.

c. The FIST DMD allows communication among the various communications nets. Thus, an FO on one radio net can communicate, through the FIST DMD, with a subscriber on a different radio net without changing his radio. The only requirement is that both subscribers appear in the net assignment table of the FIST DMD. Figure B-10 shows one possible configuration with the subscribers shown in the FIST DMD net assignment table. With this arrangement, it is possible, with the approval of the company FSO, for DMD A on net 2 to run a mission, with a howitzer platoon BCS (S) on net 1. The FIST DMD provides the communications link between nets 1 and 2.

Figure B-9. FIST DMD

d. Except for the relay function, all traffic is addressed to the FIST DMD (F in Figure B-10). The company FSO decides which subscribers can communicate with each other and under what circumstances this communication will be allowed. For example, if DMD A initiates a fire request, the company FSO may decide that the battalion mortars are the proper choice for the particular target type. The company FSO can route the fire request and all subsequent messages related to that target to the battalion mortars (R). This type of operation is called the fire request approval mode.

e. There are two other modes of operation. Before DMD A started the fire request, the company FSO could have decided that all traffic from DMD A should automatically be routed to another subscriber; for example, the battalion FDC. This is called the automatic mode. The company FSO also could have placed DMD A in the review mode. In this mode, all traffic from a subscriber (for example, DMD A) must be viewed by the company FSO. The company FSO then has the choice of forwarding the unaltered traffic to another subscriber (for example, battalion FDC), changing the text of the traffic and forwarding it to another subscriber, or terminating the message.

f. Thus, some of the decisions that were previously made at the battalion TACFIRE level are now made by the company FSO. The FIST DMD gives the company FSO the means to use and coordinate his local resources, provide the necessary communications links, and reduce the traffic volume at the battalion TACFIRE level.

Figure B-10 TYPICAL NET ASSIGNMENTS

B-22. FUNCTIONAL DESCRIPTION

In addition to its other functions, the FIST DMD can be used as an FO DMD. All operations that are possible with an FO DMD are also possible with the FIST DMD. In addition, expanded capabilities are provided. These capabilities, which are unique to the FIST DMD, are explained in the following paragraphs.

a. FIST Location. The FIST location, easting, northing, and altitude, can be entered in the FIST DMD any one of three ways. If the absolute grid location of the FIST is known, it can be manually entered directly into the FIST DMD. The second method involves observation of a single known point in calculating the FIST location. The observation data may be entered manually through the keyboard or automatically from the G/VLLD. The FIST location also can be determined by use of observations to two known points. The calculation necessary to determine the FIST location in grid coordinates is done automatically by pressing one key of the FIST DMD. The location calculated is displayed in the STATUS display of he FIST DMD and is used in converting polar data to grid lata.

b. Polar to Grid Conversion. The FIST DMD operator may convert polar data to grid data. He can convert following message types:

  • From ATI POLAR to ATI GRID.

  • From FR POI AR to FR GRID.

  • From FR LASER to FR GRID.

For example, the FIST DMD operator may use his laser range frnder to supply polar data in an FR LASER message he is composing. He may transmit the completed FR LASER message, or he may choose to have the FIST DMD automatically convert it to an FR GRID message before he transmits it.

c. Mission Buffers. The MSN1 and MSN2 buffers are the only two buffers from which messages can be transmitted; only one of these buffers can be active at a time. Unlike the FO DMD, a mission can be initiated in the active mission buffer and then stored in the off-line message files. When done in this manner, the mission data are also stored in the off-line file, and the file is protected against any changes. When a message that was originally composed in a mission buffer is moved from the off-line message files back to the active mission buffer, the current message in he active mission is destroyed. The mission data in the off-line file are also transferred along with the message. Using this feature, it is possible to interrupt a mission and start a new one. When the new mission is completed, the old mission can be resumed without loss of data.

d. Message Files. As with the FO DMD, the message files, F3 through F9, can be used for off-line message composition. A unique feature of these buffers in the FIST DMD is that a mission data file is associated with each buffer.

e. Message Transfer. Just as with an FO DMD, messages also can be composed directly in the off-line message files. However, in this case, a separate mission data buffer is not associated with the composed message. Also, when the message is transferred to the active mission buffer, the current message in the active mission buffer is destroyed and the message that is transferred uses the mission information in the active mission data file. The message that was composed in the off-line message file is not erased from the message file when it is transferred to the active mission buffer. However, active missions that were transferred to the message files are erased from the message files when they are moved back to the active mission buffer.

EXAMPLE

A priority Copperhead mission is stored in buffer F3. There is a mission data file associated with buffer F3 that contains data such as target number, time of flight, and mission number. These data are used in the composition of several diiferent messages when this mission is running. MSN1 buifer is active, and the FIST DMD operator is running a non-Copperhead mission. In the middle of this mission, the Copperhead priority target appears. The FIST DMD operator decides that the target is more important than the mission he is currently running. He files the active mission. This moves the message in the MSN1 buffer and the associated mission data to a message file. Then message file F3 is activated. This moves the message and associated mission data from buffer F3 to the active buffer, MSN1. The proper mission data and message are now in the active mission buffer, MSN1, and the active mission data file. The Copperhead mission can be completed. After completion of the Copperhead mission, the old mission can be resumed by repeating the message or data transfer procedure.

f. File Protection. If a message is composed in an active mission buffer and stored in off-line files or is currently in the active mission buffer, it will be protected from changes. If a Copperhead-related message or an FPF message that was originally composed in the active mission buffer is stored in the off-line files, it will be shown in the MESSAGE FILES display with an underlined C for Copperhead or an underlined F for an FPF mission. Other types of missions that were originally started in the active mission buffer and then transferred to the off-line message files are indicated by an underlined A in the MESSAGE FILES display. Any attempt to change any of these stored messages or to file another message in the same file will cause an error message to be displayed. It will state either CANNOT CHANGE FILED ACTIVE MSN or ACTION WOULD DELETE FPF OR COPPERHEAD PRIORITY MESSAGE.

Section IV

MORTAR BALLISTIC COMPUTER M23

B-23. DESCRIPTION

The MBC (Figure B-11) is hand-held, lightweight, and battery-powered. It is used for automated computations, digital communications, and displaying mortar-related information.

B-24. CAPABILITIES

The MBC performs the following functions:

  • Communicates with the DMD and FIST DMD.

  • Computes firing data.

  • Computes and applies meteorologieal corrections.

  • Applies registration corrections.

B-25. MEMORY STORAGE

The MBC storage contains the following:

  • Three active fire missions.

  • Three messages.

  • Eighteen weapons (three sections with up to six weapons each).

  • Twelve forward observers.

  • Fifty known points or registrations.

  • Sixteen registration points.

  • Ten no-fire zones.

  • Three FPFs.

  • Three safety fans.

  • One no-fire line (eight points eaeh).

B-26. DMD SUPPORTED MISSION PROCESSING

The MBC transmits and receives digital communications from DMDs or FIST DMDs. This capability reduces mission processing time and provides a more secure communications network. The MBC receives and processes digital fire requests (FR) and subsequent adjust (SA) messages. It can transmit ACK, MTO, and shot or splash messages.

Figure B-11. MORTAR BALLISTIC COMPUTER M23

Section V

SPECIAL PURPOSE POWER SOURCES

B-27. VEHICLES

The DMD AN/PSG-2A and the FIST DMD AN/PSG-5 may be operated with 24-volt DC vehicular power. A receptacle cable assembly unique to each device listed herein is available for connection to vehicle receptacles. (The DMD may be connected directly to the vehicle battery terminals by using a battery cable assembly.)

NOTES:

1. Refer to the operator's manual for each of the above devices before connecting electrical power because of the characteristics peculiar to each device.

2. Operator's manual references are for the DMD, TM 11-7440-281-12&P and for the FIST DMD, TM 11-7025-244-12&P.

3. Maintenance of vehicular power sources is critical with the additional drain of energy. Periodic checks and recharging of batteries are required. The appropriate type of vehicle operator's manual should be referenced for proper care of electrical systems.

B-28. INTERNAL BATTERIES

Sealed, rechargeable, nickel-cadmium (NICAD) batteries (BB-557/U) are issued for the DMD. A nonrechargeable lithium battery BA-5557/U (paragraph B-30) may also be used. The NICAD operating capacity varies depending on the storage time, energy level, temperature, and charge-discharge cycles.

NOTES:

1. Before NICAD batteries are recharged, they should be discharged if they have not been in the normal mode of operation or in storage. This is to avoid "memory" effects.

2. NICAD maintenance and recharging requirements for normal and extended operational needs must be considered. Refer to the appropriate TM for recommended maintenance.

B-29. EXTERNAL BATTERIES

The DMD may be powered by an external lithium battery BA-5590/U (paragraph B-30) or a NICAD battery BB-S90/U. The batteries which can be used internally (BB-557/U and BA-5557/U) may also be used externally.

B-30. SPECIAL HANDLING PROCEDURES FOR LITHIUM BATTERIES

a. Description. The BA-5557/U and BA-5590/U batteries are high-energy power sources that contain lithium metal, sulfur dioxide, and organic solvents under pressure in sealed stainless steel cells. The contents are potentially flammable and noxious.

b. Safety Features.

    (1) The batteries are protected by a 1.0-ampere slow-blow replaceable fuse to protect against excessive currents or external short circuits. These could lead to overheating, cell venting, or rupture. This fuse should not be bypassed or replaced with a higher rated fuse.

    (2) Each cell has a venting device which releases internal cell pressure if it becomes excessive. Venting occurs when the cells are overheated (200 to 220F). This prevents the cells from rupturing. If a cell vents, sulfur dioxide gas, which is a noxious eye and respiratory irritant, will be released. Irritation will occur long before toxic concentrations of sulfur dioxide are reached. These batteries contain no radioactive materials.

c. Precautions.

    (1) Storage. Lithium batteries should be stored in a well-ventilated, cool facility. Refrigeration is not required. Battery life decreases with storage time and increasing temperatures. For this reason, temperatures above 130F should be avoided.

    (2) Handling. Lithium batteries contain pressurized cells similar to aerosol cans. To avoid cell rupture, the batteries should not be deliberately opened, crushed, punctured, disassembled, or otherwise mutilated. Lithium batteries should not be heated or incinerated, as overheating may cause cell venting or rupture. Under no circumstances should the batteries be recharged.

    (3) Transportation. Shipment of lithium batteries is regulated by TM 38-250.

    (4) Disposal. Lithium batteries are environmentally harmful. Therefore, users must turn them in to support maintenance for proper disposal.

    (5) Overheating. In the unlikely event you detect the battery compartment becoming unusually hot, hear cells venting, or smell sulfur dioxide, take the following actions.

  • Turn off the DMD.

  • Carefully remove or disconnect the battery from the DMD, and place it away from equipment and personnel.

  • If the battery cannot be removed, place the DMD away from other equipment and personnel.

(6) Fire. Fires in which lithium batteries are involved can generally be extinguished by using enough water to "flood" the burning materials. Exposed lithium metal will burn and may not respond to the water treatment. A graphite compound will extinguish burning lithium. Carbon dioxide extinguishers are ineffective against lithium fires.

(7) Removal. When the DMD uill not be used for 30 days or more, the lithium battery should be removed.

Section VI

MNEMONICS

B-31. DMD, FIST DMD, AND FED MNEMONICS

Table B-1 shows mnemonics used by the DMD, the FIST DMD, and the FED.

Table B-1. MNEMONICS USED BY THE DMD, THE FIST DMD, AND THE FED

Table B-1. MNEMONICS USED BY THE DMD, THE FIST DMD, AND THE FED (Continued)

Table B-1. MNEMONICS USED BY THE DMD, THE FIST DMD, AND THE FED (Continued)

Table B-1. MNEMONICS USED BY THE DMD, THE FIST DMD, AND THE FED (Continued)

Table B-1. MNEMONICS USED BY THE DMD, THE FIST DMD, AND THE FED (Continued)

Table B-1. MNEMONICS USED BY THE DMD, THE FIST DMD, AND THE FED (Continued)

Table B-1. MNEMONICS USED BY THE DMD, THE FIST DMD, AND THE FED (Continued)

Table B-1. MNEMONICS USED BY THE DMD, THE FIST DMD, AND THE FED (Continued)

B-32. TARGET EQUIVALENTS

Table B-2 equates common target descriptions with an appropriate DMD, FED, and FIST DMD mnemonic. The target's primary function or weapon, not the most vulnerable characteristic, should be used to describe the target. (For example, for BRDM with Sagger, use RKTMSL/ATANK, not VEH/RECON).

Table B-2. TARGET EQUIVALENTS



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