16 line message format

Historical Development

U.S. Army Field Manual FM 24-5 Basic Field Manual, Signal Communication

U.S. Army Field Manual FM 24-17 Tactical Communications Center Operations

U.S. Army Field Manual FM-24-19 Radio Operator's Handbook (Chapter 5: Operating Procedures)

Messages were formerly prepared on DD Form 173/4, Joint Message Form

DD Form 1753, Master Station Log would be used to record some types of data for the radio station.

DD Form 1765, Incoming Service Message Log would be used to record received messages.

DD Form 1766, Outgoing Service Message Log would be used to record outgoing messages.

Current Definition and Usage

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.

ACP-124 (messages relayed by telegraphy)

ACP-125 defines the format of messages relayed by voice

ACP-126 defines the format of messages relayed by radio teletype

ACP-127 defines the format of messages relayed by automated tape

Military Affiliate Radio Service

Example Messages

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:

Example message in four different formats:

Historical Development

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", 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.