ZAA - You are not observing proper circuit discipline.

ZAB - Your speed key is improperly adjusted.

ZAC - Cease using speed key.

ZAD - Your operating signal (made at ...) received as ... (1. Not understood - 2. Not held.)

ZAE - I am unable to receive you. - Receipt through...

ZAF - Will you patch me through - -
- - - - - I am about to patch you through - to...(via you or...)? - - - - - to...(via...)

ZAG - Break...(1. Go ahead with next tape; - 2. Go back...feet; 3. Advance your key tape to reference mark number and repeat last transmission (or transmission...).

ZAH - Unable to relay message...in present form. We file. Transmit correctly prepared tape under new number to all addressees (or to...).

ZAI - Run...(1. Caller; 2. Test tape; 3. Synchronising tape; 4. Traffic tape; 5. Marking signals; 6. Spacing signals; 7. Reversals; 8. Run teletypewriter space bar signals).

ZAJ - I have (or...has) been unable to break you.

ZAK - Transmission on...kHz (or MHz) suspended until...(or was suspended at...) on account of electrical hazards.

ZAL - I am closing down (until...) due to...

ZAM - I am unable to obtain reply from teleprinter switchboard...(for connection to...). Request you call him (or other intermediate switchboard) for me.

ZAN - Transmit only messages of and above precedence...

ZAO - I cannot understand your speech. Use radiotelegraph.

ZAP - Shall I work...(1. Simplex; etc)
- - - - - Work...(1. Simplex; 2. Duplex; 3. Diplex; 4. Multiplex; 5. Single Sideband; 6. With auto-Sideband; 6. With automatic error correction system; 7. Without automatic error correction system.

ZAQ - The last word (or group)... (1. Received from you was...; 2. Transmitted to you was...)

ZAR - This is my...request (or reply). (1. First; 2. Second; 3. Third; etc.)

ZAS - Rerun all tapes run on...since (1. Your present frequency; 2.... (or MHz); 3. Callsign...; 4. This channel or...channel).

ZAT - Am preparing traffic (perforating tape) for transmission.

ZAU - What is the teletype range of my signal(s)? - - - - -
- - - - - Teletype range taken on your signal(s) is...to...

ZAV - Transmit traffic for me (or for...) by broadcast method until further directed (or until...).

ZAW - Shall I transmit 12 inches of blank tape at short intervals at...words per minute? - - - - -
- - - - - Transmit 12 inches of blank tape at short intervals at...words per minute.

ZAX - You are...(1. Causing interference. Listen before sending. 2. Causing interference by inattention to order to wait; 3. Sending at the same time as...(callsign); 4. Causing delay by slowness in answering. 5. Causing delay by slowness in answering my service or procedure messages; 6. Answering out of turn).

ZAY - Transmit traffic to me (or to... on...kHz (or MHz) without waiting for receipts. I (or...) will receipt your traffic later (on...kHz) (or MHz)).

ZAZ - One or more transmitters, simultaneously keying on this broadcast, are defective but transmission will continue on remaining transmitters. Traffic so transmitted will be repeated when full service is restored.

ZBA - What is the cause of delay (or of bad transmission)?
- - - - - Delay (or bad transmission) due to...

ZBB - For following message you will require a total of...copies.

ZBC - You are transmitting a continuous (1. Mark; 2. Space).

ZBD - Will you repeat what you (or...) sent (at...)?
- - - - - Following is what I (or...) sent (at...).

ZBE - Retransmit message...to... (for...) 1. Action; 2. Information).

ZBF - For following message use large message forms.

ZBG - You are transmitting in upper case.

ZBH - Make preliminary call before transmitting traffic.

ZBI - Listen for radiotelephony.

ZBJ - Unassigned

ZBK - Are you receiving my traffic clear?
- - - - - I am receiving your traffic... (1. Clear; 2. Garbled).

ZBL - I am unable to receive you while I am transmitting. Do not use breakin procedure.

ZBM Place...on watch on this frequency. (1. A qualified speed key operator; (2. A competent operator).

ZBN - Your...is reversed. (1. Tape; 2. Mark & Space).

ZBO - Of what precedence(s)? - - - - -
- - - - - I have (or...has)...(numeral followed by precedence prosign for each precedence) message(s) for you.

ZBP - Your...(1. Characters are indistinct; 2. Spacing is bad).

ZBQ - When and on what frequency was message...received?
- - - - - Message...was received at...on... kHz (or MHz).

ZBR - Shall I send by... (1. Direct (R) method; 2. Broadcast (F) method; 3. Intercept (I) method; 4. Repeat back (G) method)?
- - - - - Send by...(1. Direct (R) method; 2. Broadcast (F) method; 3. Intercept (I) method; 4. Repeat back (G) method.

ZBS - Your...(1. Dots are too heavy; 2. Dots are too light; 3. Dots are varying in bias; 4. Dot spacing is bad.; 5. Dots are missing; 6. Dots are blurring).

ZBT - How do you count following text group(s)...?
- - - - - Text group(s) should be counted as...group(s).

ZBU - Report when you are in radio communication with...

ZBV - Answer me (or...) on...kHz (or MHz).

ZBW - Will you shift (or ask...to shift) to transmit on...kHz (or MHz).
- - - - - I am (or...) is shifting to transmit on...kHz (or MHz).

ZBX - Will you shift (or ask...to shift) to receive on...kHz (or MHz).
- - - - - I am (or...) is shifting to receive on...kHz (or MHz).

ZBY - Pass...(1. On boradcast...; 2. On broadcast...single operator; 3. On broadcast... two operator period; 4. On broadcast...general periods only).

ZBZ - What is the printing accuracy of my signals (or those of...)?
- - - - - The printing accuracy of your signals (or those of...) is...(1. Totally corrupt; 2. Very corrupt; 3. Partly corrupt rendering traffic unacceptable; 4. Occasionally corrupt but traffic acceptable; 5. Perfect – no corruption).

ZCA - Unassigned  ((See DSSCS "Z" Signals at the bottom of the list.))

ZCB - Unassigned

ZCD - Unassigned

ZCD - Unassigned

ZCE - Unassigned

ZCF - Unassigned

ZCG - Unassigned

ZCH - Unassigned

ZCI - Unassigned

ZCJ - Unassigned

ZCK - Unassigned

ZCL - Unassigned

ZCM - Unassigned

ZCN - Unassigned

ZCO - Unassigned

ZCP - Unassigned

ZCQ - Unassigned

ZCR - Unassigned

ZCS - Unassigned

ZCT - Unassigned

ZCU - Unassigned

ZCV - Unassigned

ZCW - Unassigned

ZCX - Unassigned

ZCY - Unassigned

ZCZ - Unassigned

ZDA - I have a formal message for you. (precedence is...).

ZDB - Expedite reply(ies) to my...(1. Previous operating signal; 2. Request(s) for repetition and correction; 3. Service message...).

ZDC - Does the last message (or message...) require a signal of execution?
- - - - - Last message (or message...) requires a signal of execution.

ZDD - Bring message...to the circuit.

ZDE - Message...undelivered...(1. Will continue efforts to effect disposal; 2. Advise disposition; 3. Will not continue further efforts. Request cancel and file; 4. Give more complete address.

ZDF - Message...was received by... (addressee designation) at...Z or was (1. Received by action addressee(s) at...Z; 2. Received by information addressee(s) at...Z; 3. Received by all addressees at...Z; 4. Received by action addressee(s) message center at...Z; 5. Received by information addressee(s) message center at...Z; 6. Received by all addressees' message center at...Z; 7. Delivered by broadcast at...Z; 8. Forwarded by commercial means at...Z; 9. Mailed at...Z).

ZDG - Accuracy of following message(s (or message...) is doubtful. Correction or confirmation will be forthcoming.

ZDH - Request corrected copy of message be forwarded to...

ZDI - Place this message (or message...) on (1. MERCAST; 2. MERCAST one operator period).

ZDJ - How many groups does your message contain?
- - - - - I have a message containing...groups to transmit to you (or to...).

ZDK - Will you repeat message...(or portion...) (or will you rerun number)?
- - - - - Following repetition (of...) is made in accordance with your request.

ZDL - Confirmation...(1. Was omitted; 2. Differs from text).

ZDM I am holding your message...

ZDN - Report disposal of message...your your station with any reason for delay.

ZDO - I could not send message...to...

ZDP - Hold my message...until correctness is confirmed.

ZDQ - Message...was relayed to...at...by...(on...kHz (or MHz)).

ZDR - This is a multiple-address or book message tape containing...routing indicators in the routing line, which is to be routed in accordance with the established doctrine.

ZDS - Message (or message...) which you have (or...has) just forwarded incorrectly transmitted. Correct version of message (or part) is ……

ZDT - Exercise messages are not to be sent until further orders (or until...).

ZDU - Pass the following...(1. Private message (telegram); 2. Service telegram...) (Number of words charged for is...).

ZDV - Private message (telegram) received for...Request instructions.

ZDW In addition to the regular broadcast times, this hydrographic message is to be transmitted on the following hydrographic schedules... (1...schedule; 2. All schedules on... (date); 3. All schedules from...to... (dates inclusive)).

ZDX - Messages up to and including serial (or circuit) number...have been previously transmitted.

ZDY - Private messages (telegrams) are not to be sent until further orders. (or until...).

ZDZ - On...(date) message(s) was (were) mailed to...(command(s)) bearing serial numbers...

ZEA - Pass plain language copy to...by secure means.

ZEB - This is a reprocessed ICAO message.

ZEC - Have you received message...?
- - - - - Message...(1. Not received; 2.Unidentified. Give better identifying data).

ZED - The following confirmatory information as received is at variance with the text.

ZEE - Request message...be transmitted.

ZEF - This message has been read (received or intercepted) from a ship at sea.

ZEG - This message is not to be decrypted or reported outside the communication center in...(1. Agressor force; 2. Friendly force).

ZEH - Accuracy of...portion of following message (or message...) is doubtful. Correction or confirmation will be forwarded when received.

ZEI - Accuracy is doubtful of heading of message received as follows...Check to station of origin if necessary and repeat.

ZEJ - Replies to this message (or message...) are to be sent now (or at...).

ZEK - No answer is required.

ZEL - Is message...a correction to message...which was previously transmitted with doubtful or missing (words)?
- - - - - This message is a correction (to message...) (transmitted to...)
- - - - - Note: May only be used in conjunction with ZDG.

ZEM - Unassigned  ((See DSSCS "Z" Signals at the bottom of the list.))

ZEN - This message has been delivered by a separate transmission or by other means (1. Messenger/courier; 2. Mail) to the addressee(s) immediately following this operating signal.

ZEO - Transmit this message by rapid means when no charges are involved and to all others by mail.

ZEP - This message (or message...) was was incompletely received. Each word or group missed, which is indicated by position of ZEP in the message, will be forwarded as soon as obtained.

ZEQ - Your message...has been missent to this station...(1. Request you retransmit to correct addressee; 2. I will retransmit to correct addressee).

ZER - This is a multiple-address or book message tape containing...routing indicators in the routing line for which the station called in the pilot is responsible.

ZES - Your message...has been received... (1 Incomplete; 2. Garbled). Request retransmission.

ZET - Message has been protected and no further action by...is required.

ZEU - Exercise (drill) message.

ZEV - Request you acknowledge message...
- - - - - Message (or message...) is acknowledged.

ZEW - Your attention is invited, for … (1. Action; 2. Information) to message...which is in your files.

ZEX - This is a book message and may be delivered as a single-address message to addressees for whom you are responsible.

ZEY - This message (or message...) has been (or will be) put on the... broadcast schedules (serial number...).

ZEZ - When delivery is effected of this book message to addressee by commercial means, or when copy is forwarded to confirm message previously delivered by telephone, it is to be sent as a single address message. (May only be used in conjunction with ZEX).

ZFA - Following message has been read (received or intercepted).

ZFB - Pass this message to...(1. On arrival; 2. On return to base) (BASEGRAM)

ZFC - Have you received (or sent) the executive signal ("Execute") for message...
- - - - - Executive signal ("Execute") for last message (or following message) has been made (or was made at...).

ZFD - This message is a suspected duplicate.

ZFE - Pass message...(which is in your files) to addressee(s) for whom you are responsible using the indicated supplementary heading.

ZFF - Inform me when this message (or message...) has been received by... (addressee designation) or by... 1. Action addressee(s); 2. Information addressee(s); 3. All addressee(s); 4. Action addressee's/addressees' message center; 5. Information addressee's/addressees' message center; 6. All addressees' message center).

ZFG - This message is an exact duplicate of a message previously transmitted.

ZFH - This message (or message...) is being (or has been) passed to you (or..) for...(1. Action; 2. Information; 3. Comment) (at the request of...)

ZFI - Is there any reply to message...?
- - - - - There is no reply to message.

ZFJ - Message(s)...number(s)...not transmitted on this schedule (or on schedule...) are no longer needed.

ZFK - Does message...(or station serial number...) concern me?
- - - - - Message...(or station serial number ...)...(1. Does not concern you (or...); 2. No longer concerns you.

ZFL - Was there any traffic addressed to me on...broadcast schedule between serial numbers... and...?
- - - - - Following traffic was addressed to you on...broadcast schedule between serial numbers...and...

ZFM - Message(s) serial number(s)...(to...) which was (were) transmitted during unserviceability of one or more transmitters, simultaneously keyed, will now be repeated.

ZFN - Unassigned

ZFO - Message...is being delivered as a basegram message.

ZFP - Basegram.

ZFQ - Two messages (...and...) received under channel number (or station serial number)... Both released.

ZFR - Cancel transmission...(made under channel or station serial number...).

ZFS - Make message...same channel or station serial number as this procedure message.

ZFT - Message...received without channel number (or station serial number) following message bearing channel number (or station serial number)... Both released.

ZFU - Channel numbers...and...preceeded message... Lower number recorded and higher number blanked.

ZFV - Message...containing channel number ...separated by portions of the message, released subject to correction. Take necessary action to provide corrected copy.

ZFW - BLANK channel number(s)...Forward message...as channel number...

ZFX - Channel number (or station serial number)...is open.

ZFY - Unassigned

ZFZ - Unassigned

ZGA - What is my callsign for use on this circuit only?
- - - - - Your callsign for use on this circuit only is...

ZGB - Send (answer)...(1. In alphabetical sequence of callsigns. Each station to make its callsigns once (or...times); 2. In the following sequence of callsigns).

ZGC - Unassigned

ZGD - Two stations are using the same indefinite callsign on...kHz (or MHz). Both stations are to select different callsigns.

ZGE - Send your callsign(s) once (or... times) on this frequency (or on ..kHz (or MHz)).

ZGF - Make callsigns more distinctly.

ZGG - What is callsign of... (1. Friendly striking force aircraft; 2. Friendly shadowing aircraft; 3. Incoming vessel; 4. Senior officer present afloat (or Officer in command); 5. Ship acting as flagship for...)?
- - - - - Callsign of...is...(1. Friendly striking force aircraft; 2. Friend shadowing aircraft; 3. Incoming vessel; 4. Senior officer present afloat (or Officer in command); 5. Ship acting as flagship for...)

ZGH - I am using this transmitter to answer calls on two or more frequencies. Answer to calls may be delayed.

ZGI - I am or have been (or...is or has been) calling you (on...kHz (or MHz)).

ZGJ - When will you call me again on present frequency (or on - ...kHz (or MHz))?
- - - - - I will call you again as soon as possible (or at...) on present frequency (or on...kHz (or MHz)).

ZGK - When shall I call you again on present frequency (or on ...kHz (or MHz))?
- - - - - Call me again at...on present frequency (or on...kHz (or MHz)).

ZGL - ...will answer calls for me (or for...).

ZGM Did you (or...) hear...at...? - I have (or...has) been unable to communicate with...(since...).

ZGN - When was I (or...) last heard? -
- - - - - Nothing heard from you (or...) (since...).

ZGO - What is my number and sequence of answering?
- - - - - Your number is... Answer after number... (Numbers are to be separated by separative sign).

ZGP - Answer calls for me on present frequency (or on...kHz (or MHz)).

ZGQ - Unassigned

ZGR - Unassigned

ZGS - Unassigned

ZGT - Unassigned

ZGU - Unassigned

ZGV - Unassigned

ZGW Unassigned

ZGX - Unassigned

ZGY - Unassigned

ZGZ - Unassigned

ZHA - Shall I decrease frequency very slightly (or...kHz) to clear interference?...
- - - - - Decrease frequency very slightly (or kHz) to clear interference.

ZHB - Shall I increase frequency very slightly (or...kHz) to clear interference?...
- - - - - Increase frequency very slightly (or kHz) to clear interference.

ZHC - Unassigned

ZHD - Unassigned

ZHE - Unassigned

ZHF - Unassigned

ZHG - Unassigned

ZHH - Unassigned

ZHI - Unassigned

ZHJ - Unassigned

ZHK - Unassigned

ZHL - Unassigned

ZHM - Unassigned

ZHN - How do you receive my automatic transmission?
- - - - - Your automatic transmissions are... (1. Good; 2. Fair; 3. Unreadable).

ZHO - What is your speed of automatic transmission? - - - - -
- - - - - My speed of automatic transmission in...(1. Revolutions per minute; 2. Words per minute; 3. Bauds) is...

ZHP - What is preventing automatic reception?
- - - - - Automatic reception is prevented by ...

ZHQ - Please listen for me on...kHz (or MHz) and transmit to me on...kHz (or MHz).

ZHR - Is my speed of automatic transmission correct?
- - - - - Your speed of automatic transmission is...(1. Fast; 2. Slow; 3. Erratic; 4. Correct).

ZHS - Unassigned

ZHT - Unassigned

ZHU - Unassigned

ZHV - Unassigned

ZHW Unassigned

ZHX - Unassigned

ZHY - Unassigned

ZHZ - Unassigned

ZIA - This message (or message...) is being (or has been) passed out of proper sequence of station serial numbers.

ZIB - Two messages...and... (or group counts and time of origin...and...), both received as serial number... What are correct serial numbers?
- - - - - Change station serial number of message...to read number...OR Assign to message...station serial number...

ZIC - What is (are) station serial number(s) or channel number(s) of last message(s) you transmitted to me? -
- - - - - Station serial number(s) or channel number(s) of last message(s) transmitted to you (or to...) is (are)...

ZID - What is (are) station serial number(s) or channel number(s) of last message(s) received from me.
- - - - - Station serial number(s) or channel number(s) of last message(s) received from you (or from...) is (are)...

ZIE - Station serial number(s) or channel number(s) (from...) has (have) not been received. Repeat message(s) or cancel serial number(s) or channel number(s).

ZIF - I (or...) did not use serial number(s).

ZIG - Is (are) number(s)... (to...) blank?
- - - - - Number(s)...(to...) is (are) blank.

ZIH - Repeat headings of message number ...to...transmitted by you (or...) to check serial numbers.

ZII - What was...of your (or...'s) number...? (1. Date-time group; 2. Filing time)? -
- - - - - My (or...'s) number...had following ...(1. Date-time group; 2. Filing time).

ZIJ - I am now changing my channel number/letter. Last number sent in this series is that of this message.

ZIK - This is a weather controlled message which is not to be transmitted in the clear over radio circuits.

ZIL - Unassigned

ZIM Unassigned

ZIN - Unassigned

ZIO - Unassigned

ZIP - Have set continuous watch, or (1. Single operator period; 2. Two operator period; 3. General periods only; 4. Reduced single operator periods) on broadcast indicated. First serial number received is...
- - - - - No number yet received.

ZIQ - Unassigned

ZIR - Unassigned

ZIS - Unassigned

ZIT - Unassigned

ZIU - Unassigned

ZIV - Unassigned

ZIW - Unassigned

ZIX - Unassigned

ZIY - Unassigned

ZIZ - Unassigned

ZJA - Read signalling light of...

ZJB - May I close down visual at...). - -
- - - - - Close down visual watch now (or watch now (or at...)?

ZJC - Repeat all flag signals made by the senior officer (senior officer present afloat).

ZJD - Use...(1. Better light; 2. Better background).

ZJE - Set visual watch now (or at...).

ZJF - Visual relaying station between senior officer (senior officer present afloat) (or...) and...is to be...

ZJG - Repeat all flashing (or semaphore) messages made by the senior officer (senior officer afloat).

ZJH - Your light is unreadable...(1. Not trained correctly; 2. Not bright enough; 3. Too bright).

ZJI - What are the callsigns of the ships in company with you? - -
- - - - - Callsigns of teh ships in company with me are...(For visual use only).

ZJJ - Use double-flash procedure.

ZJK - Are you (or is...) visual guard for...? -
- - - - - I am (or...is) visual guard for...

ZJL - Hoist the following signal.

ZJM - ...(1. Flaghoist; 2. Semaphore; 3. 20-inch signalling projector; 4. 10-inch signalling projector; 5. ALDIS; 6. Intermediate; 7. Heather; 8. Daylight signalling lantern; 9. Masthead flashing light; 10. Infrared; 11. Signal searchlight; 12. Omnidirectional flashing light; 13. Directional flashing light)

ZJN - Message...has been passed to those for whom I am responsible (or to...) (at...) but "L" has not been received.

ZJO - Repeat back each group of the text of this message as it is transmitted.

ZJP - Message which follows is to be encrypted and passed to all addressees (by...). (Only to be used by visual not liable to interception).

ZJQ - Repeat signal (or message...) the senior officer (senior officer present afloat) (or ship indicated) is now transmitting or is about to transmit.

ZJR - Only semaphore is to be used for visual signalling between...and ...(or from...).

ZJS - Directional lights of minimum brillance are to be used for all visual traffic between...and...except for messages of precedence priority and above requiring transmission to two or more ships.

ZJT - Broadcast transmitter indicated is about to be taken off for...minutes (or until...).

ZJU - Unassigned

ZJV - Unassigned

ZJW Unassigned

ZJX - Unassigned

ZJY - Unassigned

ZJZ - Unassigned

ZKA Who is controlling station (net control station) on this frequency (or on... kHz (or MHz))? -
- - - - - I am (or...is) controlling station (net control station) on this frequency (or on...kHz (or MHz)).

ZKB - Is it necessary to obtain the permission of the controlling station (net control station) before transmitting messages? -
- - - - - It is necessary to obtain the permission of the controlling station (net control station) before transmitting messages.

ZKC - Substitute code sign (callsign) of control station of group (net) in place of this operating signal.

ZKD - Shall I take control of net (for...) (until...)?
- - - - - Take control of the net (for...) (until...).

ZKF - Station leaves net temporarily (or for...minutes) (to communicate with...) (will be on...kHz (or MHz)).

ZKG - Observe (or direct...to obeserve) schedule with...on...kHz (or MHz) (at...).

ZKH - Did you (or...) observe schedule with...at...?
- - - - - I (or...) observed schedule with ...(at...).

ZKI - Set watch on...kHz (or MHz)... (1. Continuous; 2. Until further notice).

ZKJ - May I close down (until...)?
- - - - - ...(1. Close down (until...); 2. I am closing down (until...))

ZKK - Assume radiotelegraph (wireless) organisation...forthwith (or at...)

ZKL - Resume normal radio communication now (or at...).

ZKM - Take guard (for...) (on...kHz (or MHz)).

ZKN - I have taken over guard on...kHz (or MHz).

ZKO - I have handed over guard (to...) (on ...kHz (or MHz)). (Serial number of last message received was...

ZKP - Are you (or is...) radio guard - I am (or...is) radio guard for...for... (on...kHz (or MHz))?

ZKQ - Indicate ships or stations for which you are (or...is) guard. (1. Radio (on...kHz (or MHz)); 2. Visual).

ZKR - On what frequencies are you (or...) maintaining watch?
- - - - - I am (or...is) maintaining watch on ...kHz (or MHz)).

ZKS - What stations are keeping watch on...kHz (or MHz) (or are in net)? -
- - - - - Following stations are keeping watch on...kHz (or MHz) (or are in net).

ZKT - Am keeping watch on...kHz (or MHz) for...(1. First five minutes in each half hour; 2. From 10 to 15 and 40 to 45 minutes past the hour; 3. Between...and...minutes past the hour).

ZKU - I am (or...is) maintaining continuous watch, or (1. Single operator period; 2. Two operator period; 3. General periods only; 4. Reduced single-operator period) on...(callsign)... Broadcast.

ZKV - I am (or...is) standing splitphone watch on...and...kHz (or MHz).

ZKW - Unassigned

ZKX - Unassigned

ZKY - Unassigned

ZKZ - Unassigned

ZLA - I have pictures of the following types to tranmsit...(1. Photographs; 2. Weather maps; 3. Blueprints; 4. Printed matter; 5. Test).

ZLB - What drum rotation speed shall I use? - - - - - -
- - - - - Transmit at...revolutions per minute. (1. 30; 2. 45; 3. 50; 4. 60; 5. 90; 6. 100)

ZLC - Your transmission...(1. Shows objectional modulation; 2. Suitable for communication but not for picture; 3. Shows caption too close to edge of picture; 4. Shows buckled print; 5. Shows fork drift; 6. Picture shows too much contrast; 7. Picture shows insufficient contrast; 8. Picture shows cross-over).

ZLD - I am unable to...(1. Sychronise with you; 2. Transmit pictures; 3. Copy pictures).

ZLE - Send...(1.Fence; 2. White; 3. Black; 4. Picture; 5. Synchronise; 6. Fence swinging black; 7. Fence swinging white until I stop you).

ZLF - ...(1. Inverter; 2. Converter; 3. 96- lne 12 x 18 transceiver; 4. 100-line transceiver; 5. 300-line transceiver).

ZLG - Shall I transmit (1. Negative; 2. Positive)?
- - - - - Transmit...(1. Negative; 2. Positive).

ZLH - Will you transmit map(s)... (...area...time...type)?
- - - - - I am going to transmit mpa(s)... (...area...time...type).

ZLI - Reverse material on drum and re-run until I break you.

ZLJ - What size lettering shall I use? - - - - - - - - - -
- - - - - Use...(1. Standard telegraphic typewriter; 2. Jumbo typewriter (if available; 3. Hand lettering at least 3/16 of an inch high).

ZLK - Unassigned

ZLL - Unassigned

ZLM - Unassigned

ZLN - Facility indicated cannot be operated at present.

ZLO - Is (are) facility(ies)... operative at your station(or at...)?
- - - - - The following...facility(ies) is (are) operative at this station (or at...). 1. Homing beacon; 2. Radar beacon; 3. Revolving and/or flashing beacon; 4. Radio beacon; 5. Instrument landing system; 6. Ground control approach; 7. Approach control; 8. Tower transmitter (state which type LF, MF, VHF or UHF); 9. MF direction finder; 10. VHF direction finder; 11. UHF direction finder; 12. Runway lights; 13. Sandra lights; 14. Radio track guide; 15. Radio range).

ZLP - What is (are) the magnetic line(s) of shoot of the... (facility)?
- - - - - The magnetic line(s) of shoot of the ...(facility) is (are)... degrees.

ZLQ - Unassigned

ZLR - Unassigned

ZLS - Unassigned

ZLT - Unassigned

ZLU - Unassigned

ZLV - Unassigned

ZLW - Unassigned

ZLX - Unassigned

ZLY - Unassigned

ZLZ - Unassigned

ZMA - What was bearing of unknown station (or station using callsign...) at...(time) (on...kHz (or MHz))?
- - - - - Bearing of unknown station (or station using callsign...) was... (at...time) class...(on...kHz (or MHz)).

ZMB - Bearing of you (or of...) was... (class...) from me (or from...) at...(time).

ZMC - Bearing of station which answered message (or transmission) from... was...(at...(time)) class...(on … kHz (or MHz)).

ZMD - 1. Your bearing appears to be between ...degrees and...degrees, and sense indicates you are to the… (direction) of this station; 2. Your bearing is changing rapidly.

ZME - Pass in direction finding bearing (of...) obtained on...kHz (or MHz) (or between...and...kHz (or MHz).

ZMF - Will you endeavour to obtain a direction finding bearing of station now transmitting (or of...) (on...kHz (or MHz))?
- - - - - Bearing of station now transmitting (or of...) (on...kHz (or MHz)) was ... (class...) sense determined at...

ZMG - This bearing (course or position) is unreliable. Error in excess of class C bearing (or position) may amount to...degrees or miles).

ZMH - Surface craft using callsign... cooperating. Change to...kHz (or MHz) and follow diretion finding procedure when called.

ZMI - Will you send your callsign and dashes of five-seconds' duration at intervals in order that I (or...) may home on you?
- - - - - I am about to send my callsign and dashes of five seconds' duration at intervals in order that you (or...) may home on me.

ZMJ - Check...(1. Correctness of last QUV; 2. Sense of last QDR; 3. Correctness of last QDM; 4. Sense of last QDM).

ZMK - Cannot determine your (or...'s...) (1. Position; 2. Bearing).

ZML - Steer...degrees for 2 minutes if possible and send callsign and long dashes while you are so doing.

ZMM - Increase height to enable more accurate bearing to be completed.

ZMN - Change over to loop direction finding on...kHz (or MHz) (and home on transmissions made by...).

ZMO - What is my position by direction finding bearing from the nearest landmark (or from...)?
- - - - - Your position by direction finding cross bearings from nearest landmark (or from...) is...(class...) at... (hours).

ZMP - Endeavour to plot position from bearings taken on station(s) now transmitting (or of...) (on...kHz) (or MHz)).

ZMQ - Cannot determine your position, you are in line or nearly in line with direction finding station baseline.

ZMR - Take over direction finding guard as previously ordered (on...kHz (or MHz)) (from...to...kHz (or MHz)).

ZMS - Carry out short direction finding procedure (as locally prescribed).

ZMT - Sense determination unreliable, bearing may be reciprocal.

ZMU - 1. Listen (for...0 on direction finding on...kHz (or MHz) (or between ...and...kHz (or MHz)); 2. Shift to direction finding frequency...and listen for callsign...).

ZMV - What is the Grid Course for me to steer to reach you (or...)? - - - - - - -
- - - - - The Grid Course for you to steer to reach me (or...) is...degrees at... hours.

ZMW - Unassigned

ZMX - Unassigned

ZMY - Unassigned

ZMZ - Unassigned

ZNA - You are encrypting...incorrectly. (1. Operating signals; 2. Radio callsigns; 3. Address groups).

ZNB - What is authentication of.. (1. Message...; 2. Last transmission; 3. ...)?
- - - - - Authentication (of...) is... (1. Message; 2. Last transmission; 3. ...).

ZNC - All transmissions will be authenticated...(1. On all circuits; 2. On this circuit; 3. On...frequency).

ZND - You are using authenticator incorrectly...(1. Verify authenticator system key; 2. Check authentication of your last transmission).

ZNE - I am prepared to authenticate.

ZNF - Addressees who are not holders of the cryptographic system employed in the text need not decrypt (decipher), but shall sight (read) translation at first opportunity and obtain copy if applicable.

ZNG - Commands who are included in the collective address used in this heading, who are not holders of the cryptographic system employed in the text, are exempted.

ZNH - Plaintext tape of this message should be prepared during process of decipherment.

ZNI - Shift to...(1. On-line; 2. Plain) operation now.

ZNJ - Unassigned

ZNK - Addressees who do not hold cryptogaphic facilities are exempted.

ZNL - Receiving Cryptographic Office concerned should refer queries relating to the text of this mssage (e.g. requests for verification) to...(address designators except plain language). Note: To be used in codress messages when necessary to indicate originating crypto center and then normally limited to messages of Immediate precedence and above.

ZNM Originator authorises the transfer o this message into the secure networks of all authorities addressed, provided the networks are secured or approved for the security classification of the message involved.

ZNO - Unable to decrypt message... (from indefinite callsign...). Note: Only to be used under circumstances lid down in cryptographic instructions.

ZNP - Transfer operation of channel now to...(1. Normal; 2. Top Secret; 3. Conference; 4. Engineering;) on-line cipher operation. Note: This signal is for use only wen already in on-line operation.

ZNQ - This message (or message...) received at this station... (1. Without authentication (when authentication is in force); 2. Incorrectly authenticated).

ZNR - This message may be forwarded without change by radio or non-approved circuit.

ZNS - Unassigned

ZNT - Unassigned

ZNU - Unassigned

ZNV - Unassigned

ZNW - Unassigned

ZNX - Unassigned

ZNY - Unassigned

ZNZ - Unassigned  ((See DSSCS "Z" Signals at the bottom of the list.))

ZOA - Relay this message (or message...) by visual (to...).

ZOB - Take (I will take) no further action regarding forwarding message...

ZOC - Station(s) called relay this message to addressees for whom you are responsible.

ZOD - Act as radio link (relaying station) between me and...(or between...and ...).

ZOE - Can you accept message for...? (1. On-line; 2. Off-line)
- - - - - Give me your message. I will dispose o it...(1. On-line; 2. Off-line).

ZOF - Relay (pass) this message (or message...) to...now (or at...).

ZOG - Transmit (pass) this message (or message...) to...(for...) (1. Action; 2. Information).

ZOH - Send message for...on...kHz (or MHz) by...(1. Receipt method; 2. Broadcast method; 3. Intercept method).

ZOI - Pass this message to the nearest (or...) weather central/control.

ZOJ - Unable to relay message...in present form...(1. Callsigns not encrypted; 2. Text not encrypted).

ZOK - Relay this message via...

ZOL - I will relay your callsign to senior officer present afloat, whose callsign is...

ZOM - Delivery of this message by mail in lieu of broadcast permissable (to...).

ZON - Place this message (or message...) on...(1. Continuous wave broadcast; 2. Radioteletype broadcast) indicated by following specific broadcast designator(s)...

ZOO - Place this message (or message...) on MERCAST indicated by following specific broadcast designator(s).

ZOP - This message (or message...) has been delivered to all broadcast areas (or to the following specific broadcast area(s)...).

ZOQ - Deliver this message (or message...) to all broadcast areas (or to the following specific broadcast area(s)...).

ZOR - 1. Route traffic for...via...area broadcast; 2. Beginning at... traffic for you (or...) will be routed via...area broadcast.

ZOS - Request area routing for messages for...
- - - - - Area routing for messages for... is...

ZOT - Transmit or handle this message at the lower precedence to the station or address designator(s) which follow(s).

ZOU - How should traffic for... be routed. - - - - - -
- - - - - Route traffic for...through...(on... kHz (or MHz)).

ZOV - Station designation preceding this operating signal is the correct routing for this message, rerouted by...

ZOW Broadcast this message at special watchkeeping periods for ships with (1. One radio operator; 2. Two radio operators).

ZOX - Place this message (or message...) on submarine broadcast indicated by following specific broadcast designator(s)...

ZOY - Relay this message only to the station(s) whose designation(s) preceed this operating signal.

ZOZ - Relay this message (or message...) in its present form without decryption.

ZPA - Your speech is distorted.

ZPB - Your transmitter has strong radiation while idling.

ZPC - Your signals are...(1. Fading badly; 2. Fading slightly; 3. Good for... words per minute; 4. Getting
- - - - - stronger; 5. Getting weaker).

ZPD - Is your signal as checked by monitor...satisfactory (1 Locally; 2. As radiated)?.
- - - - - My signal as checked by monitor... is satisfactory (1. Locally; 2. As radiated).

ZPE - Maximum power is now being radiated.

ZPF - What is the readability of the signals of the group (net) (or of...)?
- - - - - The readability of the signals of the group (net) (or of...) is... (1 to 5).

ZPG - What is (are) signal strength(s) of group (net) (or of...)?
- - - - - Signal strength(s) of the group (net) (or of...) is... (1 to 5).

ZPH - Unassigned

ZPI - Unassigned

ZPJ - Unassigned

ZPK - Unassigned

ZPL - Unassigned

ZPM - Unassigned

ZPN - IFF switched ON in distress position.

ZPO - The text of this message is to be relayed in precisely the same format as that in which it is received.  No characters or machine functions are to be added, inserted or deleted and the relative positions of the groups are to be retained.

ZPP - Message which follows is a submarine surfacing signal to be ceared on the calling frequency.

ZPQ - Unassigned

ZPR - I have (number) messages (precedence) prepared in tape relay format for you (or for...(addressees)).
- - - - - (Consideration should be given to receiving these messages directly o a printing reperforator/typing reperforator).

ZPS - Unassigned

ZPT - This transmission is a transmitter pre-acceptance trial. Request expeditious strength and readability reply.

ZPU - If more than one tropical wind warning message in this sequence is awaiting transmission, transmit highest serial number first. (Sequence/serial is understood to include tropical warning name or number and consecutive warning number).

ZPV - If the earlier wind warnings identified by DTG(s) following this signal are awaiting transmission, file those warnings without further transmission.

ZPW - This message cancelled at time indicated. File without further transmission.

ZPX - This message is forwarded to your for screening and determination of need for broadcast promulgation.
- - - - - Advise broadcast control commander of recommended message disposition.

ZPY - Unassigned

ZPZ - Unassigned

ZQA - The landing lights at the aerodrome (or at the aerodrome at...) are out of order.

ZQB - What is the magnetic direction in which landing is to be made? -
- - - - - The magnetic direction in which landing is to be made is... degrees.

ZQC - Are you (or is...)... (1. Airborne; 2. Waterborne; 3. On land)?
- - - - - I am (or...is)...at...(time). (1. Airborne; 2. Waterborne; 3. On land).

ZQD - Am I to carry out the procedure appropriate to the use of the...(facility)?
- - - - - You are to carry out the procedure appropriate to the use of the... (facility).

ZQE - What is your desired rate of descent expressed in hundreds of feet per minute?
- - - - - My desired rate of descent is... hundreds of feet per minute.

ZQF - What is the length in yards of the runway in use?
- - - - - The length of the runway in use is ...yards.

ZQG - Unassigned

ZQH - Unassigned

ZQI - Unassigned

ZQJ - Unassigned

ZQK - Unassigned

ZQL - Unassigned

ZQM - Unassigned

ZQN - Unassigned

ZQO - Unassigned

ZQP - Unassigned

ZQQ - Unassigned

ZQR - Unassigned

ZQS - Unassigned

ZQT - Unassigned

ZQU - Unassigned

ZQV - Unassigned

ZQW - Unassigned

ZQX - Unassigned

ZQY - Unassigned

ZQZ - Unassigned

ZRA - How does my frequency check? -
- - - - - Your frequency is...(1. Correct; 2. Slightly (or...Hz (or kHz)) high; 3. Slightly (or...Hz (or kHz)) low; 4. Stable on steady mark; 5. Stable on steady space; 6. Unstable; 7. Erratic).

ZRB - Check your (or...'s) frequency on this circuit (or on...kHz (or MHz)).

ZRC - Shall I tune my transmitter to...(1. Proper frequency; 2. Zero beat with your (or...) transmitter)?
- - - - - Tune your transmitter to...(1. Proper frequency; 2. Zero beat with my (or...) transmitter).

ZRD - What is the frequency of the... radio facility now in operation?
- - - - - The frequency of the...radio facility now in operation is...

ZRE - On what frequency do you hear me best? -
- - - - - I hear you best on...kHz (or MHz).

ZRF - Will you send tuning signal on your present frequency (or on ...kHz (or MHz)) for one minute or until AS is given? -
- - - - - Am about to send tuning signal on my present frequency (or on...kHz (or MHz)).

ZRG - When will a change of frequency (to...kHz (or MHz)) be necessary?
- - - - - A change in frquency (to...kHz (or MHz)) will be necessary at approximately...

ZRH - Is my frequency shift correct? -
- - - - - Your frequency shift is...(1. Too wide; 2. Too narrow; 3. Not linear; 4. Correct) (by Hz).

ZRI - Unassigned

ZRJ - Will you check your...? - -
- - - - - I will check my...
- - - - - ((See DSSCS "Z" Signals at the bottom of the list.))

ZRK - Shall I revert to single channel working?
- - - - - Revert to single channel working.

ZRL - Are you working on the correct code? NOTE: This meaning applies only to frequency shift diplex. - - - - - - I am working on the correct code. NOTE: This meaning applies only to frequency shift diplex.

ZRM Can you receive both sidebands of my independent sideband transmissions?
- - - - - I can receive...(1. The upper sideband; 2. The lower sideband; 3. Both sidebands).

ZRN - Do you intend to transmit on... (1. The upper sideband; 2. The lower sideband; 3. Both sidebands independently)? - -
- - - - - I intend to transmit on...(1. The upper sideband; 2. The lower sideband; 3. Both sidebands independently).

ZRO - Can you read me on... (1. Channel A; 2. Channel B; 3. Channel(s)...; 4. All channel(s)?
- - - - - I can read you on...(1. Channel A; 2. Channel B; 3. Channel(s)... 4. All channel(s).

ZRP - Transfer signal on channel...to channel...

ZRQ - Change to other sideband.

ZRR - Message(s) number(s)...will no longer be broadcast but are effective and of interest (to units indicated).

ZRS - Your carrier is...(1. Over-suppressed; 2. Under-suppressed).

ZRT - Radiate full unmodulated power for...minutes.

ZRU - Are my tone frequencies correct?
- - - - - Your tone for...(1. Marking and spacing are high; 2. Marking and spacing are low; 3. Marking and spacing are correct).

ZRV - Unassigned

ZRW - Unassigned

ZRX - Unassigned

ZRY - Unassigned

ZRZ - Unassigned

ZSA - May I ascend to...(height)? - - You may ascend to...(height).

ZSB - May I descend to...(height)? - You may descend to...(height).

ZSC - Switch on IFF.

ZSD - IFF switched OFF.

ZSE - Do you have glider in tow? - -
- - - - - 1. We have glider in tow; 2. We are forced to release glider at (approximate position).

ZSF - Switch off...(1. IFF; 2. IFF sets for 10 minutes in area denoted except for ships whose callsigns follow).

ZSG - May I make an approach using the facility indicated.
- - - - - You may approach using the facility indicated.

ZSH - Unassigned

ZSI - You are...(1. To maintain height of...feet and report over...(callsign) range station; 2. To hold on ... leg of the beam...(callsign) range station at height...feet)

ZSJ - Unassigned

ZSK - Unassigned

ZSL - Unassigned

ZSM - Unassigned

ZSN - Unassigned

ZSO - Send tapes...(1. Once; 2. Twice).

ZSP - Unassigned

ZSQ - Unassigned

ZSR - Unassigned

ZSS - Unassigned

ZST - Unassigned

ZSU - Unassigned

ZSV - Unassigned

ZSW - Unassigned

ZSX - Unassigned

ZSY - Unassigned

ZSZ - Unassigned

ZTA - 1. Radio; 2. Visual; 3. Landline; 4. Teletypewriter (Teleprinter); 5. Telephone; 6. Automatic; 7. Fascimile; 8. Shore telephone; 9. Shore teleprinter; 10. Radioteletypewriter).

ZTB - 1. Tranmitter-distributor; 2. Auto-head; 3. Perforator; 4. Reperforator; 5. Printer; 6. Undulator; 7. Keyboard; 8. Frequency shift keyer; 9. Multiplexing carrier base; 10. On-line crypto device).

ZTC - Does my...appear to be faulty; 2. Is your...faulty)?
- - - - - 1. Your...appears to be faulty; 2. My...is faulty).

ZTD - Shall I use...?
- - - - - Use...

ZTE - Are you (or is...) able to use...? -
- - - - - I am (or...is) able to use...

ZTF - Are repairs completed?
- - - - - Repairs are completed.

ZTG - ...(class of emission/type of transmission).

ZTH - Unassigned

ZTI - ...(1. Receiver; 2. Transmitter; 3. Power supply; 4. Antenna system; 5. Radio direction finder).

ZTJ - Cease using...

ZTK - Are you (or is...) connected to...?
- - - - - I am (or...is) connected to...

ZTL - Are you (or is...) about to disconnect?
- - - - - I am (or...is) about to disconnect.

ZTM - I (or...) is unable to use...

ZTN - What is my bias distortion? - -
- - - - - Your bias distortion is... (1. Excessive; 2. ...percent (marking); 3. ...percent (spacing); 4. ...percent (total distortion)).

ZTO - Is my character formation correct?
- - - - - Your character formation is... (1. Correct; 2. Defective in the start element; 3. Defective in the 1st unit; 4. Defective in the 2^nd unit; 5. Defective in the 3^rd unit; 6. Defective in the 4^th unit; 7. Defective in the 5^th unit; 8. Defective in the stop element).

ZTP - What is the duration of your modulation cycle?
- - - - - The duration of my modulation cycle is...(50 Baud Equipment) -- 1. 148 milliseconds (7.42 units) fast. 2. 150 milliseconds (7.5 units) correct. 3. 152 milliseconds (7.6 units) slow. 4. ... erratic per character. (45.5 Baud Equipment) ---1. 161 milliseconds (7.35 units) fast. 2. 163 milliseconds (7.42 units) correct. 3. 165 milliseconds (7.5 units) slow. 4. ... erratic per character.

ZTQ - Will you...(1. Get the Circuit Engineer/Facility Control Technician to speak on this circuit (or circuit...); 2. Hand the line over to the Circuit Engineer/Facility Control Technician for check)? - -
- - - - - I will...(1. Get the Circuit Engineer/Facility Control Technician to speak on the circuit; 2. Hand the line over to the Circuit Engineer/Facility Technician for check and call you when check has been completed).

ZTR - Will you...(1. Disconnect your equipment from line and carry out local test, reconnecting to line in ... minutes; 2. Connect your transmit line to your receive line to enable me to carry out a loop test for...minutes)?
- - - - - I will...(1. Disconnect (or I am disconnecting) my equipment from and carry (or to carry) out local test, reconnecting to line in... minutes; 2. Connect my transmit line to my receive line to enable you to carry out a loop test for... minutes).

ZTS - Is the line satisfactory? - -
- - - - - The line is...(1. Satisfactory; 2. Unsatisfactory).

ZTT - Unassigned

ZTU - Unassigned

ZTV - Unassigned

ZTW Unassigned

ZTX - Unassigned

ZTY - Unassigned

ZTZ - Unassigned

ZUA - Request a timing signal now (or at...)
- - - - - Timing signal will be transmitted now (or at...). The numerals indicating the time will be followed by a five-second dash terminating exactly at the time indicated.

ZUB - At...

ZUC - From...to...

ZUD - Until further orders (or until...).

ZUE - Affirmative (Yes).

ZUF - Air raid...(1. Warning; 2. In progress; 3. All clear).

ZUG - Negative (No).

ZUH - Unable to comply.

ZUJ - Stand by.

ZUK - (Appointment Code) desires key conversation on this circuit with...(Appointment Code). Will you indicate when you are ready?
- - - - - Appointment Code) is now ready to begin key conversation with... (Appointment Code).

ZUL - Unassigned

ZUM - Unassigned

ZUN - Unassigned

ZUO - Unassigned

ZUP - Unassigned

ZUQ - Unassigned

ZUR - Unassigned

ZUS - Unassigned

ZUT - Unassigned

ZUU - Unassigned

ZUV - Unassigned

ZUW - Unassigned

ZUX - Unassigned

ZUY - Unassigned

ZUZ - Unassigned

ZVA - Station called is responsible for relay or delivery to all stations in line two (2) or to stations indicated.

ZVB - What was your time over last compulsory reporting point, and ETA at next compulsory reporting point?
- - - - - My time over last compulsory reporting point was...and my ETA at next compulsory reporting point is...

ZVC - Unassigned

ZVD - Unassigned

ZVE - What are the security conditions of your termination(s) of this channel (or...channel/circuit designated)?
- - - - - Security conditions at my termination of this channel (or...channel/circuit designated) are...(1. Secured for Restricted; 2. Secured for Confidential; 3. Secured for Secret; 4. Secured for Top Secret).

ZVF - This channel (or...channel/circuit designated) is unserviceable for classified traffic.

ZVG - Unassigned

ZVH - Unassigned

ZVI - Unassigned

ZVJ - Unassigned

ZVK - Unassigned

ZVL - Unassigned

ZVM - Unassigned

ZVN - Unassigned

ZVO - Unassigned

ZVP - Unassigned

ZVQ - This message, relating to a warning, an alert, distress, or an emergency, is authorised to be relayed via the facilities of your network without prior arrangement.

ZVR - Retransmit this message (or message ...) at once to all subordinate stations.

ZVS - Unassigned

ZVT - Unassigned

ZVU - Unassigned

ZVV - Unassigned

ZVW - Unassigned

ZVX - Unassigned

ZVY - Unassigned

ZVZ - Unassigned

ZWL - No forwarding action to the designation(s) immediately following is required.

ZWM Correct answer to last question (or question...) is...(or will be found in...).

ZWN - Correct version of the part of the last message (or message...) which was sent incorrectly is...(or will be found in...).

ZWO - Following message (or question, or exercise) is for the exercise of (1. Junior operators; 2. Senior operators; 3. Ratings on watch).

ZWP - A junior operator is to carry out... (1. A standard flashing exercise; 2. A standard semaphore exercise; 3. A standard radio telegraphy transmitting exercise; 4. A standard radio telegraphy receiving exercise).

ZWQ - Unassigned

ZWR - Unassigned

ZWS - Unassigned

ZWT - Unassigned

ZWU - Unassigned

ZWV - Unassigned

ZWW Unassigned

ZWX - Unassigned

ZWY - Unassigned

ZWZ - Unassigned

ZXA - The following group is a callsign, delivery group or an address group. (Used in plain language texts of messages other than procedure messages.

ZXB - Station(s) to whom this message is routed obtain a complete copy of this interrupted transmission by addressing a service message to the originating station.

ZXC - Unassigned

ZXD - This message is to be delivered to the addressee(s) in tape form.

ZXE - Unassigned

ZXF - Unassigned

ZXG - Unassigned

ZXH - Unassigned

ZXI - Unassigned

ZXJ - Unassigned

ZXK - Station called relay this message (or message...) to...in addition to predetermined responsibilities.

ZXL - Unassigned

ZXM - Unassigned

ZXN - Unassigned

ZXO - Request you obtain retransmission of messages...from station...

ZXP - I have for you...(1. A request for direct air support; 2. A reply to a support request. Precedence is...).

ZXQ - I have for you...(1. A request for tactical reconnaisance; 2. A request for photographic reconnaisance; 3. A request for artillery reconnaisance. Precedence is...)

ZXR - Extensive flag signalling will take place shortly (or in...minutes).

ZXS - Message which follows is to be handled by...(Officer Emergency Cryptographic team; 2. Ratings Emergency Cryptographic team; 3. Senior Communications Rating; 4. Junior Communications Rating; 5. Coder (Educational)).

ZXT - This message is not to be transmitted by radio telegraph or radiotelephone in any form over part of its route.

ZXU - Unassigned

ZXV - Unassigned

ZXW - This message has been delivered to all action addressees whose designations follow this operating signal.

ZXX - This message has been delivered to all information addressees whose designations follow this operating signal.

ZXY - Transmit this message to the addressee(s) indicated by the numeral(s) following... All addressees are to be counted consecutively as they appear (numbers to be separated by the Separative Sign).

ZXZ - Unassigned

ZYA thru ZZZ - Reserved for assignment as required by national authorities.
((See DSSCS "Z" Signals at the bottom of the list.))

==========================================================
Exerpted from Communications Technician "O" 3&2, Rate Training Manual (NAVEDTRA 10235-C), Revised 1975, Appendix VI:

In addition to operating signals which are assigned meanings in the current edition of ACP-131, the following signals and assigned meanings are authorized for use in DSSCS.

ZCA - This is an exact duplicate of a message which has been forwarded via physical means.  (1. to ............. )

ZEM - Used in message format as a symbol for machine recognition of the start of text (SOT) indicator, which prevents the incoming line sensing device from reacting to certain machine sequences during the textual portion of a message.

ZRJ - Urgent operating condition.  Used to attract the attention of a distant station.  Receipt of this signal will activate an alarm at those stations where incoming circuits are equipped with the model 28 printer. to avoid unnecessary alarms, use of this operating signal must be limited to conditions of urgency.

ZYH - Used in message format as a high precedence indicator, which activates an alarm upon receipt of an IMMEDIATE, FLASH or CRITIC precedence message.