My old copy of ACP 131 is divided by tab markers for easy reference. It's version B, with Changes 1-5, and is dated in 1976. It provides both encode and decode for both Q and Z Signals. The Q-Signals are for civilian use and the Z-Signals for military use.
I’ve had this old document for decades. It’s an older version with Changes 1 – 5, with Change 5 dated 28 April 1976, which was just before I went into the Air Force, so I’m presuming I got it then. I put it here for its historical value, because it reflects current usage back then. The most up-to-date version can be found here at the DoD DTIC website.
I’ve organized this the same way my book is organized: using tabs. Also, accessing the book a little at a time makes each section download more quickly. Clicking on a link brings up the section in another browser tab. Once you close that tab, you should come back here.
Note that although this is a nice, clear, sharp scanned copy, the text is selectable and copyable.
INTRODUCTION
Q-SIGNALS DECODE
- QAA – QBZ
- QCA – QDZ
- QEA – QFZ
- QGA – QHZ
- QIA – QJZ
- QKA – QLZ
- QMA – QNZ. Please note that amateur radio operators have created their own set of QNx signals for net operation. You can see these by going here at the ARRL site and scrolling down toward the bottom.
- QOA – QQZ (reserved for the maritime services)
- QRA – QSZ
- QTA – QUZ
- QVA – QZZ (reserved)
Z-SIGNAL DECODE
- ZAA – ZBZ
- ZCA – ZDZ
- ZEA – ZFZ
- ZGA – ZHZ
- ZIA – ZJZ
- ZKA – ZLZ
- ZMA – ZNZ
- ZOA – ZPZ
- ZQA – ZRZ
- ZSA – ZTZ
- ZUA – ZVZ
- ZWA – ZXZ
ENCODE
- Search and Rescue
- Radio Navigation
- Direction Finding
- Aeronautical and Sea Operations
- Meteorology
- Communications Equipment and Circuits Adjusting and Testing
- Circuit Discipline and Net Control. See also the ham-radio-specific list of Q-signals used for net control here at the ARRL site (scroll down toward the bottom).
- Message Handling
- Security and Cryptographic
- Visual
- Exercise and Miscellaneous
- Miscellaneous Abbreviations and Symbols (Both Decode and Encode)
- Series ZYA – ZZZ (Reserved for intra-nation, intra-service, or intra-command use)
- Designation of Emissions [Note that this section is way, way out of date!]
- List of Effective Pages [Through Change 5]
As I noted many years ago, the Q signals dealt mainly with aviation and weather, not necessarily civilian use only. Military usage of the Z signals came later, but the Q signals were used by pilots so that they could get their messages out quickly and continue to concentrate on flying their aircraft.
On a graveyard shift one night I was getting fed up with the Op at the other end sending IMI almost every line of text. I was sending traffic at approx 20 WPM. I was an instructor in CW and procedure so my fist was constant with no errors. Conditions on HF were good. I continued to re send has requested for quite some time but I was getting more and more frustrated at the “IMI” requests. That was it. I thought sod you. I sent ZBM2 on my next over and waited for a reply. I got AS AR. Then the supervisor at the other end got funny and sent a ti-raid of text at approx 30WPM. OK cleaver bugger I put my mates Bug Key in circuit and rapped off the fact that I had got traffic to send and clear with him. How long a shift is this going to be IMI IMI. Next communication was K. and I was able to clear the traffic with no more IMI’s. I think he must have stay’ed on circuit and thrown the other guy off.
Best insult was ZBM2
“Put a qualified operator on the circuit”
What a walk down memory lane! Used to spend 12hr watches in Kodiak, AK (72-73) looking at this pub! I can still remember all the watch ops!
Randy Walker, RM2, USCG
I was an aviation radioman/gunner flying in OS2U Aircraft flying in the Aleutian IS. during WWII Squadron VS-49 and I remember that ZUG meant ‘I am forced to land or alight at”
ZZO ZWH when I was in the Navy as a Radioman stated to “rephase and try again”. I understand it later went to “ZYR-1 ZWH. I believe we use to have a US SUPP to the ACP 131. Been retired almost 22 years so not sure what it is now.
As i recall ZZO was “try again”. As in “Rephase and try again” ZWH ZZO
Hi Tom, I’m wondering if ZZO was an “informal” signal, as the book lists no codes starting with ZZ. I looked in the updated ACP131 and found nothing there either.
I have looked at a lot of the ACP 131 listings and wonder if I have really lost it!?
I seem to clearly remember ZZO# An inexperienced operator is about to send signals using###
It looks like ZDL is not used for a question, but rather only as an “Answer, Advice, or Order.” It looks like it’s simply a “confirmation,” much like hams use “QSL” today. ZDL with the number 1 means “was omitted,” and ZDL 2 means “differs from text.” I can see how it could easily have been used as you describe.
What happened to “ZDL 1 and 2. USAF in late 60s and early 70s used ZDL2 for “Unable to xmit pictures?
You forgot:
INT ZZZ – “Are you asleep”. Or, at least, that’s what we in the U.S. Navy translated that to when someone on the other end couldn’t “get it”.
Thanks for the post. Brought back some good memories.
Lupe Torres
RMCS USN (Ret.)