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.
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
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
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
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
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.
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).
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
ZEN AAA0USA/AAA0W WA
8 INFO ZEN AAA6TN TX
ZEN AAA6TS TX
9 XMT AAT6USF TX
10 GR 23
14 CFN ...
15 C ...
Figure 1. Standard 16-Line Message Format.