16-line message format,orBasic Message Format, is the standard military radiogram format (inNATO allied nations) for the manner in which a paper message form is transcribed through voice, Morse code, or TTY transmission formats. The overall structure of the message has three parts: HEADING (which can use as many as 10 of the format's 16 lines), TEXT (line 12), and ENDING. This heading is further divided into procedure, preamble, address, and prefix. Each format line contains pre-defined content. An actual message may have fewer than 16 actual lines, or far more than 16, because some lines are skipped in some delivery methods, and a long message may have a TEXT portion that is longer than 16 lines by itself.
This radiotelegraph message format (also "radio teletype message format", "teletypewriter message format", and "radiotelephone message format") and transmission procedures have been documented in numerous military standards, going back to at least World War II-era U.S. Army manuals.
The 16-line format and procedures for transmitting it vary slightly depending on the communications medium, but all variations are designed to be harmonious and the procedures describe how to convert (refile) between the formats.
When sent as an ACP-126 message over teletype, a 16-line format radiogram would appear similar to this:
RFHT
DE RFG NR 114
R 151412Z MAR
FM CG FIFTH CORPS
TO CG THIRD INFDIV
WD GRNC
BT
UNCLAS
PLAINDRESS SINGLE ADDRESS
MESSAGES WILL BE TRANSMITTED
OVER TELETIPEWRITER CIRCUITS
AS INDICATED IN THIS EXAMPLE
BT
C WA OVER TELETYPEWRITER
NNNN
Some of the format lines in the above example have been omitted for efficiency. The translation of this abbreviate format follows:
Format Line
Message Text
Explanation
Line 2
RFHT
Station being called, which will receive the message
Line 3
DE RFG NR 114
Sent by radio station having the callsign RFG, station serial number 114
Line 5
R 151412Z MAR
Routine precedence, March 15, 2:12pm UTC in Date-time group format
Line 6
FM CG FIFTH CORPS
The message is from CG FIFTH CORPS
Line 7
TO CG THIRD INFDIV
The message is to CG THIRD INFDIV
Line 10
WD GRNC
Accounting symbol (WD); word groups have not been counted (GRNC)
Line 11
BT
Section separator between heading and text
Line 12
UNCLAS
PLAINDRESS SINGLE ADDRESS
MESSAGES WILL BE TRANSMITTED
OVER TELETIPEWRITER CIRCUITS
AS INDICATED IN THIS EXAMPLE
Message content is unclassified, and the message is sent with a misspelled word, "TELETIPEWRITER" for example purposes.
Line 13
BT
Section separator between text and the ending
Line 15
C WA OVER TELETYPEWRITER
corrects (C) word after (WA) "OVER" to "TELETYPEWRITER"
Line 16
NNNN
end-of-message indicator
Example message in four different formats:
Format Line
Telegraph Radiogram (ACP-124)
Voice Radiogram (ACP-125)
Radioteletype Radiogram (ACP-126)
Tape Relay Radiogram
(ACP-127)
ACP-127 Supl.
1
VZCZC051 UU
VZCZC051 UU
VZCZC051 UU
2 (or 2&3)
CALLED_CALLSIGN THIS IS CALLING_CALLSIGN MESSAGE NUMBER 051
CALLED_CALLSIGN DE CALLING_CALLSIGN NR 051
RR CALLED_CALLSIGN
RR CALLED_CALLSIGN
3
DE CALLING_CALLSIGN 0051 22/1856Z
DE CALLING_CALLSIGN #0051 1121857
4
TRANSMISSION INSTRUCTIONS/OP. SIGS
ZNR UUUUU TRANSMISSION INSTRUCTIONS/OP. SIGS
ZNR UUUUU TRANSMISSION INSTRUCTIONS/OP. SIGS
5
ROUTINE TIME 221855Z APR 2015
R 221855Z APR 2015
R 221856Z APR 2015
R 221857Z APR 2015
6
FROM ORIGINATION PLAIN LANGUAGE ADDRESS
FM ORIGINATION PLAIN LANGUAGE ADDRESS
FM ORIGINATION PLAIN LANGUAGE ADDRESS
FM ORIGINATION PLAIN LANGUAGE ADDRESS
7
TO TO ADDRESSEE RI AND PLAD
TO TO ADDRESSEE RI AND PLAD
TO TO ADDRESSEE RI AND PLAD
TO TO ADDRESSEE RI AND PLAD
8
INFO INFORMATION ADDRESSEE 1 RI AND PLAD INFORMATION ADDRESSEE 2 RI AND PLAD
INFO INFORMATION ADDRESSEE 1 RI AND PLAD INFORMATION ADDRESSEE 2 RI AND PLAD
INFO INFORMATION ADDRESSEE 1 RI AND PLAD INFORMATION ADDRESSEE 2 RI AND PLAD
INFO INFORMATION ADDRESSEE 1 RI AND PLAD INFORMATION ADDRESSEE 2 RI AND PLAD
The concept of the standard message format originated in the wired telegraph services. Each telegraph company likely had its own format, but soon after radio telegraph services began, some elements of the message exchange format were codified in international conventions (such as Articles 9, 22, 26, 29, 30, and Appendix 1 of the International Radiotelegraph Convention, Washington, 1927), and these were then often duplicated in domestic radio communications regulations (such as the FCC in the U.S.) and in military procedure documentation.
Military organizations independently developed their own procedures, and in addition to differing from the international procedures, they sometimes differed between different branches of the military within the same country.
For example, the publication "Communication Instructions, 1929",[6] from the U.S. Navy Department, includes:
One procedure for messages transmitted "in naval form over nonnaval systems" (Part II: Radio, Chapter 15)
One procedure for exchanging messages with commercial radio stations (Part II: Radio, Chapter 16, pages 36–37 for examples; see also Part I: Chapter 7)
One procedure for messages transmitted within the Navy (Part IV: Procedure and Examples, Chapter 32, especially pages 21 & 22 for the format)
One format for exchanging messages between the Army and Navy (Part IV: Appendix A), called the "Joint Army and Navy Radiotelegraph Procedure", with the format shown on page 70.
