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Z code

{{for|the virtual machine language introduced by Infocom|Z-machine}}

{{use dmy dates|date=November 2023}}

{{short description|Morse code operating signal of the US Army / NATO}}

Z Code (like Q Code and X Code) is a set of operating signals used in CW, TTY and RTTY radio communication.

Distinct versions

There are at least three sets of Z codes.

:

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| 1.

| One set of codes was originally developed by Cable & Wireless Ltd. (the Cable & Wireless Service Z code) for commercial communications in the early days of wire and radio communications.

:

Many of the old C&W codes are derived from mnemonics

: (ZAL = alter wavelength,
ZAP = ack please,
ZSF = send faster, etc.)

:

The old C&W Z codes are not widely used today.

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| 2.

| APCO{{clarify|date=November 2023}} also developed a system of Z codes.{{cite web |title=Standard Z Signals |website=APCO International Historical Collection (apcohistory.org) |url=http://www.apcohistory.org/apco-collection/search/profile/article/A28953}}

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| 3.

| NATO forces independently developed a later set of Z codes for military use and inter-language needs. The NATO Z codes are still in use, and are published in the unclassified document ACP-131.

There are other sets of codes internally used by Russia's military and other operating agencies.

Examples

:

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|+ {{big|Some example Z codes}}

Code

! Meaning

! Source

{{nobr| ZAL (...) ... }}

| I am closing down (until ...) {{nobr|due to ...}}

| C&W

ZAP ...

| Work ...

: 1. Simplex;
2. Duplex;
3. Diplex;
4. Multiplex;
5. Single sideband;
6. With automatic error correction system;
7. Without automatic error correction system.
8. With time and frequency diversity modem

| C&W

ZBK

| Are you receiving my traffic clear?

| NATO

ZBK 1

| I am receiving your traffic clear

| NATO

ZBK 2

| I am receiving your traffic garbled

| NATO

ZBM 2

| Place a competent operator on this circuit

| C&W

ZLD 2

| I cannot transmit pictures

| C&W

{{nobr|ZSF ... (...) }}

| Switch off ... (except ...)

: 1. IFF;
2. IFF sets for 10 minutes in area denoted except for ships with the following {{nobr|call signs ...}}

| C&W

ZBW ...

| Change to backup frequency ...

| C&W

ZBZ ...

| Measure of printability

: 1=Garbled / unreadable, up to 5=Perfect

| C&W

ZUJ

| Stand by.

| NATO

See also

References

External links

  • [http://www.kloth.net/radio/zcodes.php Ralf D. Kloth DL4TA – List of Z-codes]
  • [https://web.archive.org/web/20120906015123/http://jcs.dtic.mil/j6/cceb/acps/acp131/ACP131F.pdf ACP 131(F) – Communications Instructions Operating Signals]

{{Morse code}}

Category:Operating signals

Category:Encodings

Category:Morse code