THE STANDARD 16-LINE MESSAGE FORMAT by G. O. Ellis, AAT6VF The Standard 16-Line Message Format is described in detail in Table 10-3 of FM 11-490-7. There is a great deal of information in this table which may be unfamiliar to many MARS operators. The discussion to follow is intended to point out some of the subtle points in the Manual concerning message format and to help members in understanding the use of the format. The Auto-Refiler software was written initially to assist in the handling of high volumes of traffic, which is usually transmitted by digital means (RATT, AMTOR, PACKET, etc), and following discussion of the Standard 16-Line Format will be based on the RATT procedures applicable to these modes. Let us begin by first explaining the difference between a Multiple-Address message and a Book message. (a) A Multiple-Address message is one addressed to two or more addressees, one or more of which are "Action Addressees". Such a message may also contain "Information Addressee(s)". Use of this type of message is necessary when each addressee needs to be informed of the identity of all other addressees involved. (b) A Book message is a message sent to several addressees and containing the same text information, but is sent to each addressee as a single-address message, with no requirement for each addressee to be informed of the identity of other recipients of the message. Operators are NOT AUTHORIZED to convert Multiple-Address messages to Book message format, by changing the "TO", "INFO", and "XMT" lines unless specifically directed to do so in Format Line 5 by use of the operating signal "ZEX". This operating signal is a message handling instruction placed in Format Line 5 by the originator. Message handling instructions are NOT to be changed by stations in the relay chain. (see FM 11-490-7, para. 10-9d(3)). Figure 1 shows an example of a multiple-address message. All format lines do not appear in every message; however, when used they are to be in the order indicated. In the example, the number of the applicable format line is shown to the left of the page. This column of numbers is not a part of the message itself. FORMAT LINE 1 is not normally used in MARS messages. When used, it may include such items as security warning prosigns, operating signals and address designations as required. FORMAT LINE 2 contains the callsigns of the called stations, or a collective call such as a net call. When appropriate, this line may contain the callsigns of exempt stations. In the example, the transmitting station has called an entire net and has indicated that AAA6TN is exempt. 1 FORMAT LINE 3 contains the prosign "DE", the callsign of the sending station, the prosign "NR", and the Station Serial Number (SSN) of the message. Additional information, such as the operator's identification, where more than one operator uses the same station callsign, may appear on this line. Each operator in the relay chain must receipt for the message and assign his own SSN to the message before retransmitting (see paragraph 12-6b of the Field Manual FM 11-490-7). In the example, the operator's initials are shown following the message number, or SSN. Operator's initials should not be included where the transmitting station has only one operator using that callsign. Such use has no significance and takes up additional transmission time on the air. FORMAT LINE 4 contains transmission instructions, when appropriate. These transmission instructions may include the prosigns "G" or "F", the prosign "T" alone or in conjunction with callsigns as necessary, operating signals, etc. Where more than one instruction is used in a message, each must appear on a SEPARATE LINE. In the example, AAR6AC is instructed to relay the message to AAR6XZ. FORMAT LINE 5 contains the precedence and Date-Time Group. In the case of dual-precedence messages, both prosigns are shown separated by a space. Message handling instructions, when used, are included following the Date-Time Group and are in the form of operating signals. Message handling instructions should be used, when possible, rather than "operator's notes". Operator's notes are not authorized by FM 11-490-7. In the example, the operating signal "ZFD", meaning "this message is a suspected duplicate", is used. FORMAT LINE 6 is the "FROM" line, and contains the prosign "FM" followed by the designation of the message originator, either plain text or callsign. It may also include an "office symbol" in the case of official traffic. The office symbol is usually enclosed between double-slants (//). The callsign of the originating station follows the last slant (/) in the line, and may be followed by an abbreviation of the country or state where the originating station is located. In the example, the originator is the Central Area MARS Director, the office symbol is "ASQN-OP-RC-SHN", and the station of origin is AAA6USA, located in Texas. FORMAT LINE 7 is the "TO" line of the message. It contains the prosign "TO" followed by the designation of the Action addressee or addressees. Routing indicators and operating signals may be included. Address designators are indicated by plain language, routing Address Indicator Groups, or call signs. In the case of multiple-address messages, when addressees are listed individually each address designation will be on a separate line and may be 2 preceded by either the operating signal "ZEN" (meaning delivered by other means) or by the routing indicator (callsign) of the station responsible for delivery. Routing indicator callsigns are separated from the Action Addressee by a slant bar (/). Such use is mandatory on all joint and combined addresses. In the example, callsign of the station responsible for delivery to each addressee is shown preceding the addressee designation, for example: TO AAA3USA/AAA3E MD indicates AAA3USA is responsible for delivery of the message to the Eastern Area Director, AAA3E. The operating signal "ZEN" precedes the appropriate address designations. The collective address designation "AIG 4170" indicates a "standard" list of addressees, similar in use to a standard "mailing list". This type of addressee designator will not normally be found in messages ORIGINATED by affiliate members, but could perhaps be found in official traffic RELAYED by affiliate members. FORMAT LINE 8 is the "INFO" line. The above discussion concerning Format line 7 applies to Format line 8, except the addressees are Information Addressees. A collective address designation (such as "ALL SMD CENTRAL AREA") or an AIG in Format line 7 may include information addressees. FORMAT LINE 9 is the "EXEMPT" line. It is used only when a collective address designation is used in line 7 or 8, or an AIG is used in line 7 and an indication of the addressee(s) exempted from the collective address or AIG is required. FORMAT LINE 10 is the "GROUP COUNT" line. It is used when required, and consists of the prosign "GR" followed by the number of countable groups in the text of the message. The group count prosign and group count will be used only when the text consists of countable encrypted groups. (See ACP 121 series). FORMAT LINE 11 consists of the prosign "BT" and is used to separate the heading from the text of the message. FORMAT LINE 12 is the text of the message. It may consist of more than one line and may include Classification, internal instruc- tions, and the thought or idea expressed by the originator, in that order. FORMAT LINE 13 is the prosign "BT". It separates the message text from the ending. FORMAT LINE 14 is the Confirmation line. It is used in RATT operations to repeat preceding portions which may be easily misunderstood or otherwise received incorrectly. Usual practice in the handling of third-party traffic is to repeat the entire "TO" line of the message. 3 FORMAT LINE 15 is the "Correction" line. It is used to correct errors not previously noted. This line should not be used when transmitting messages or message files previously prepared. The proper procedure in these cases is to "edit" the message files prior to transmission and correct any errors. The correction line may be used in the RARE event that direct keyboard transmission of the message is involved. FORMAT LINE 16 is the "End-of-Message" line. It consists of the end-of-message indicator "NNNN", preceded by the appropriate number of blank lines (see FM 11-490-7). 4 STANDARD-FORMAT MESSAGE FORMAT LINE MESSAGE =========== ==================================================== 1 (Not used in MARS) 2 AAA6USA/H XMT AAA6TN 3 DE AAT6USE NR 0158 LXY 4 AAR6AC T AAR6XZ 5 PP 211546Z OCT 90 ZFD 6 FM DIRCENTRAL AREA MARS//ASQN-OP-RC-SHN//AAA6USA TX 7 TO AAA3USA/AAA3E MD AAA3USA/AAA3B MD ZEN AAA0USA/AAA0W WA AIG 4170 8 INFO ZEN AAA6TN TX ZEN AAA6TS TX AAA6OK OK AAA6AR AR AAA6LA LA AAA6NM NM 9 XMT AAT6USF TX 10 GR 23 11 BT 12 TEXT " " 13 BT 14 CFN ... 15 C ... 16 NNNN Figure 1. Standard 16-Line Message Format.