Procedure word

"WILCO" redirects here. For other uses, see Wilco (disambiguation).

Procedure words or prowords are words or phrases limited to radio telephone procedure used to facilitate communication by conveying information in a condensed standard form.

Universal prowords

Affirm, Affirmative

"Confirm" or "Yes", used in Aviation. Some air arms of military forces also use a "double click" sent over the radios by keying the mic twice to produce a "--" like Morse code, this is usually used when the pilot is unable to talk due to heavy workload or stress.

Clear

In amateur radio transmissions, the transmitting station's call sign followed by the word "clear" is used to indicated the sending station is done transmitting and leaving the airways, alias turning off the radio.

Negative

"No" or "NEG". Because over a poor quality connection the words "affirmative" and "negative" can be mistaken for one another (for example over a sound-powered telephone circuit), United States Navy instruction omits the use of either as prowords. Sailors are instructed to instead use "yes" and "no".

Out

"This is the end of my transmission to you and no answer is required or expected."

Over

"This is the end of my transmission to you and a response is necessary. Go Ahead: transmit."

Contrary to popular belief, "Over" and "Out" are never used at the same time, since their meanings are mutually exclusive. Therefore, "Over and Out" should never be used together in radio communications. Historically, the term "Over and Out" was used to mean "Over to you, and when you're done, I'm Out." With spring-loaded PTT buttons on modern combined transceivers, the same meaning can be communicated with just "Out", as in "Ops, Alpha, ETA five minutes. Out."

Roger, Received, Romeo, Copy

"I have received your last transmission satisfactorily, radio check is loud and clear." "Roger" is used occasionally to mean "yes", but this is incorrect. The proper proword for "yes" is "Affirm".

Romeo, although incorrect, has the same meaning, but is used mainly in Australian Maritime Operations. Use of the correct prowords "Roger" or "Received" should be encouraged.

For Maritime VHF, Copy does not mean the same as Roger or Received. It is used when communications between 2 other stations which includes information for your station that has been overheard and received satisfactorily.

Send

"I have received your initial call; send me your message."

Wilco

"I understand and will comply." WILL COMPLY is shortened into WILCO. To be used only by the addressee.

Note that "ROGER" and "WILCO" used together are redundant, since WILCO includes the acknowledgement of ROGER.

Maritime/amateur VHF prowords

Radio check

What is my signal strength and readability; how do you hear me?

5 by 5 is an older term used to assess radio signals, as in 5 out of 5 units for signal strength and for readability. Other terms similar to 5x5 are "loud and clear" or "Lima and Charlie". Example:

ALPHA 12: X-RAY Two-Three, THIS IS ALPHA One-Two, RADIO CHECK, OVER

X-RAY 23: ALPHA One-Two, THIS IS X-RAY Two-Three, I READ YOU 5 BY 5, OVER

ALPHA 12: ALPHA One-Two ROGER, OUT

US Army correct check:

ALPHA 12: X-RAY Two-Three, THIS IS ALPHA One-Two, RADIO CHECK, OVER

X-RAY 23: ALPHA One-Two, THIS IS X-RAY Two-Three, ROGER OUT

If the initiating station (ALPHA 12 in the example) cannot hear the responding station (X-RAY 23 above), then the initiator attempts a radio-check again, or if the responder's signal was not heard, the initiator replies to the responder with "NEGATIVE CONTACT, ALPHA 12 OUT".

The following readability scale is used: 1 = Bad (unreadable); 2 = Poor (readable now and then); 3 = Fair (readable but with difficulty); 4 = Good (readable); 5 = Excellent (perfectly readable).

Amateur radio

Amateur radio operators use a different scale, called R-S-T, for readability, strength and tone (the latter only used with CW transmission, the best rating being 5-9-9.

Read back for check

Instruction to receiving station to read back the information it has received for confirmation. Same as HOW COPY. Reply from receiving station will be preceded by I READ BACK or I COPY, confirmation by transmitting station takes the form of the proword CORRECT or GOOD COPY. See example 2, below. The U.S. Army uses "HOW COPY" only.

Say again

"I have not understood your message, please say again". Usually used with prowords ALL AFTER or ALL BEFORE. Example: radio working between Solent Coastguard and a motor vessel, call-sign EG 93, where part of the initial transmission is unintelligible

- All stations, all stations, this is Solent Coastguard, Solent Coastguard. Be advised large shipping vessel entering Southampton Water, currently at position ...[transmission unintelligible]...Out.

- Solent Coastguard, Solent Coastguard, this is Echo Golf Niner Three. Say again all after position. Over.

At this juncture, Solent Coastguard would reply, giving the position of the shipping vessel preceded with the prowords I SAY AGAIN:

- All stations, All stations, this is Solent Coastguard. I say again, large shipping vessel entering Southampton water, currently at position one decimal two miles from Calshot Spit on bearing one six five degrees. Vessel restricted in ability to deviate from its course. Do not impede. Out.

Note that the word "REPEAT" is never to be used in place of SAY AGAIN, except in aviation, where pilots say "Please say again" or "please repeat". (It's just a short-cut instead of saying "please repeat") especially in the vicinity of naval or other firing ranges, as REPEAT is an artillery proword with a wholly different meaning. However, REPEAT may be used in the middle of a signal to emphasise information. Example:

EG93: Victor Juliet Five-Zero, this is Echo Golf Niner-Three. How much fuel do you require? Over.
VJ50: Echo Golf Niner-Three, this is Victor Juliet Five-Zero. I require six five - repeat six five - litres of diesel. Over.
Or alternatively:
VJ50: Echo Golf Niner-Three, this is Victor Juliet Five-Zero. I require six five litres of diesel. Repeat six five litres. Repeat diesel. Over

However, given the above stricture on using 'REPEAT', it is better to use 'I SAY AGAIN' or 'WORDS TWICE' or 'FIGURES TWICE', as in:

VJ50: Echo Golf Niner-Three, this is Victor Juliet Five-Zero. I require six five litres of diesel. I say again six five litres of diesel. Over

Station calling

This proword is used when addressing an unidentified station which has just hailed the receiver. For example, Cowes VTS has received a transmission from an unidentified station. The correct reply would be:

"Station calling Cowes VTS, Station calling Cowes VTS - this is Cowes VTS. Over."

This is

This transmission is from the station whose designator immediately follows. For clarity, the station called should be named before the station calling. So, "Mike Juliet Zero, THIS IS Golf Whiskey Three..." or for brevity, "Mike Juliet Zero, Golf Whiskey Three, ROGER and OUT". Never "This is GW3 calling MJ0" or any other reversed combination.

So far

During transmission with lots of information, this proword can be used between transmissions, to ensure all information is passed on correctly.

Examples of radio communication using procedure words

Example 1

2 helicopters are flying in formation, Indian 610 and Indian 613:

Indian 610: "613, I have a visual on you at my 3 o'clock. 610"

Indian 613: "Roger. 613"

Indian 610: "613, Turn right to a heading of 090. 610"

Indian 613: "Wilco. 613"

Anytime a radio call is made (excepting 'standby' where the correct response is silence), there is some kind of response indicating that the original call was heard. 613's "Roger" confirms to 610 that the information was heard. In the second radio call from 610, direction was given. 613's "Wilco" means "Will comply."

It is better procedure, however, to always read back an instruction. For example, if all 613 says is "Wilco," 610 is not certain that he correctly heard the heading as 090. If 613 replies with a read back and the word Wilco ("Turn Right zero-niner-zero, Wilco") then 610 knows that the heading was correctly understood, and that 613 intends to comply, which is a safer situation.

Example 2

The following is the example of working between two stations, EG93 and VJ50 demonstrating how to confirm information:

EG93: "Victor Juliet Five-Zero, Victor Juliet Five-Zero, this is Echo Golf Niner-Three. Request rendezvous at 51 degrees 37.0N, 001 degrees 49.5W. Read back for check. Over."

VJ50: "Echo Golf Niner-Three, Echo Golf Niner-Three, this is Victor Juliet Five-Zero. I read back: five one degrees three seven decimal zero North, zero zero one degrees four niner decimal five West. Over."

EG93: "Victor Juliet Five-Zero, Victor Juliet Five-Zero, this is Echo Golf Niner-Three. Correct. Out."

Distress, urgency and safety prowords (used for maritime and aeronautical VHF)

Mayday (distress)

Main article: Mayday (distress signal)

I, my vessel or a person aboard my vessel is in grave and imminent danger, send immediate assistance. This call takes priority over all other calls.

The correct format for a Mayday call is as follows:

[The first part of the signal is known as the call]
"Mayday, Mayday, Mayday,

This is (vessel name repeated three times, followed by call sign if available)

[The subsequent part of the signal is known as the message]

Mayday (vessel name)

My position is (position as a LAT-LONG position or bearing and distance from a fixed point)

I am (type of distress, e.g. on fire and sinking)

I require immediate assistance

I have (number of people on board and their condition)

(Any other information e.g. "I am abandoning to life rafts")

Over"

VHF instructors, specifically those working for the Royal Yachting Association, often suggest the mnemonic MIPDANIO for learning the message of a mayday signal: Mayday, Identify, Position, Distress, Assistance, Number of crew, Information, Over.

In aviation a different format is used:

[First part of the message] Mayday, Mayday, Mayday

[Second part of the message] Callsign is stated at the end, followed by either "Heavy" or "Super", though this is not always necessary

[Third part of the message] Nature of the emergency

For example: Mayday, Mayday, Mayday, Air Transat 236 heavy, we have lost both of our engines, due to fuel starvation, we are gliding now.

After that pilot can give, or the controller can ask for, additional information, such as, fuel and number of passengers on board.

Pan pan (urgency)

Main article: Pan-pan

(pronounced /ˈpæn ˈpæn/)

I, my vessel or a person aboard my vessel requires assistance but is not in distress. This overrides all but a MAYDAY call, and is used, as an example, for calling for medical assistance or if the station has no means of propulsion. The correct call is:

Pan pan, Pan pan, Pan pan

All stations, all stations, all stations

This is [vessel name repeated three times]

My position is [position as a LAT-LONG position or bearing and distance from a fixed point]

I am [type of urgency, e.g. drifting without power in a shipping lane]

I require [type of assistance required]

[Any other information e.g. size of vessel, which may be important for towing]

Over

Securité (safety)

pronounced /seɪˈkjʊərᵻteɪ/ say-KEWR-i-tay

I have important meteorological, navigational or safety information to pass on. This call is normally broadcast on a defined channel (channel 16 for maritime VHF) and then moved onto another channel to pass the message. Example:

[On channel 16]

Securité, Securité, Securité.

All stations, all stations, all stations.

This is Echo Golf Niner-Three, Echo Golf Niner-Three, Echo Golf Niner-Three.

For urgent navigational warning, listen on channel six-seven.

Out.

[Then on channel 67]

Securité, Securité, Securité.

All stations, all stations, all stations.

This is Echo Golf Niner-Tree (three), Echo Golf Niner-Tree, Echo Golf Niner-Tree.

Floating debris sighted off Calshot Spit.

Considered a danger to surface navigation.

Out.

ACP 125(F) procedure words

Proword	Explanation	Prosign/ OPSIG
ACKNOWLEDGE (ACK)	An instruction to the addressee that the message must be acknowledged	ZEV or QSL
ADDRESS GROUP	The group that follows is an address group
ALL AFTER	The portion of the message to which I have reference is all that follows……………	AA
ALL BEFORE	The portion of the message to which I have reference is all that precedes…………..	AB
ANSWER AFTER	The station called is to answer after call sign……..when answering transmissions.	ZGO
ASSUME CONTROL	You will assume control of this net until further notice	ZKD
AUTHENTICATE	The station called is to reply to the challenge which follows	INT ZNB
AUTHENTICATION IS	The transmission authentication of this message is……….
BREAK	I hereby indicate the separation of the text from other portions of the message	BT
BROADCAST YOUR NET	Link the two nets under your control for automatic rebroadcast
CALL SIGN	The group that follows is a call sign
CLOSE DOWN	Stations are to close down when indicated. Acknowledgments are required	ZKJ
CORRECT	You are correct, or what you have transmitted is correct.	C
CORRECTION	An error has been made in this transmission. Transmission will continue with the last word correctly transmitted. An error has been made in this transmission (or message indicated). The correct version is…… That which follows is a corrected version in answer to your request for verification"	EEEEEEEE C C
DISREGARD THIS TRANSMISSION – OUT	This transmission is in error, disregard it. (This proword shall not be used to cancel any message that has been completely transmitted and receipted.	EEEEEEEE AR
DO NOT ANSWER	Stations called are not to answer this call, receipt for this message, or otherwise transmit in connection with this transmission. When this proword is employed, the transmission shall be ended with the proword OUT.	F
EXECUTE	Carry out the purport of the message or signal to which this applies. (To be used only with the Executive Method.)	IX-----
EXECUTE TO FOLLOW	Action on the message or signal which follows is to be carried out upon receipt of the proword EXECUTE. (To be used only with the Delayed Executive Method.)	IX
EXEMPT	The station(s) immediately following is (are) exempted from the collective call or from collective address	XMT
FIGURES	Numerals or numbers follow.
FLASH	Precedence FLASH.	Z
FROM	The originator of this message is indicated by the address designator immediately following	FM
GRID	The portion following is a grid reference
GROUPS	This message contains the number of groups indicated by the numeral following.	GR
GROUP NO COUNT	The groups in this message have not been counted.	GRNC
I AM ASSUMING CONTROL	I am assuming control of this net until further notice	ZKA
I AUTHENTICATE	The group that follows is the reply to your challenge to authehticate	ZNB
IMMEDIATE	Precedence IMMEDIATE	O
IMMEDIATE EXECUTE	Action on the message or signal following is to be carried out on receipt of the EXECUTE. (To be used only with the Immediate Executive Method.)	IX
INFO	The addressees immediately following are addressed for information	INFO
I READ BACK	The following is my response to your instructions to read back	IRB
I SAY AGAIN	I am repeating transmission or portion indicated.	IMI
I SPELL	I shall spell the next word phonetically.
I VERIFY	That which follows has been verified at your request and is repeated. (To be used only as a reply to VERIFY.)	C
MESSAGE	A message which requires recording is about to follow. (Transmitted immediately after the call. This proword is not used on nets primarily employed for conveying messages. It is intended for use when messages are passed on tactical or reporting nets.)	ZBO
MORE TO FOLLOW	Transmitting station has additional traffic for the receiving station.	B
NEGATIVE (NEGAT)	No. Cancel message(s) sent by the Delayed Executive Method. (NEGAT may be used to cancel a single message or a group of messages awaiting execution.)	ZUG
NET NOW	All stations are to net their radios on the unmodulated carrier wave which I am about to transmit.	ZRC2
NO PLAY	During exercises the words NO PLAY are used to distinguish real activity from messages concerned with exercise play e.g. a real emergency or real casualty. The first words of any message is to contain the works exercise (nickname e.g.Red Flag) NO PLAY
NOTHING HEARD	To be used when no reply is received from a call station.	ZGN
NUMBER	Station serial number.	NR
OUT	This is the end of my transmission to you and no answer is required or expected.	AR
OVER	This is the end of my transmission to you and a response is necessary. Go ahead, transmit	K
PRIORITY	Precedence PRIORITY	P
READ BACK	Repeat this entire transmission back to me exactly as received	G
REBROADCAST YOUR NET	Link the two nets under your control for automatic rebroadcast.
RELAY (TO)	Transmit this message to all addressees (or addressees immediately following this proword). The address component is mandatory when this proword is used.	T or ZOF
RELAY THROUGH	Relay your message through call sign………	ZOK
ROGER	This is a method of receipt. I have received your last transmission satisfactorily.	R
ROUTINE	Precedence ROUTINE.	R
SAY AGAIN	Repeat all of your last transmission. Followed by identification data means “Repeat………… (portion indicated).”	IMI
SEND YOUR	I am ready to receive your message, report, etc.	K
	(Used only in reply to the offer of a message, etc., on tactical or reporting nets.)
SERVICE	The message that follows is a SERVICE message	SVC
SIGNALS	The groups which follow are taken from a signal book. (This proword is not used on nets primarily employed for conveying signals. It is intended for use when tactical signals are passed on non-tactical nets.)
SILENCE (Repeated three or more times)	Cease transmissions on this net immediately. Silence will be maintained until lifted. (Transmissions must be authenticated by use of a self authenticated system, codeword, etc.)	HM HM HM
SILENCE LIFTED	Silence is lifted. (Transmissions must be authenticated by means of self authentication system, codeword, etc.)	ZUG HM HM HM
SPEAK SLOWER	Your transmission is too fast. Reduce speed of transmission.	QRS
STOP REBROADCASTING	Cut the automatic link between the two nets that are being rebroadcast and revert to normal working.
THIS IS	This transmission is from the station whose designator immediately follows.	DE
THIS IS A DIRECTED NET	From now until further notice this net is directed.	ZKB
THIS IS A FREE NET	From now until further notice this net is free.	ZUG ZKB
THROUGH ME	Relay your message through me	ZOE
TIME	That which immediately follows is the time or datetime group of the message.	QTR
TO	The addressees immediately following are addressed for action	TO
--TO--	The portion of the message to which I have reference is all that which appears between the groups………and………
UNKNOWN STATION	The identity of the station with whom I am attempting to establish communication is unknown.	AA
USE ABBREVIATED CALL SIGNS	Call signs are to be abbreviated until further notice.
USE ABBREVIATED PROCEDURE	As conditions are normal, all stations are to use abbreviated procedure until further notice.
USE FULL CALL SIGNS	Call signs are to be sent in full until further notice
USE FULL PROCEDURE	As conditions are not normal, all stations are to use full procedure until further notice.
VERIFY	Verify entire message (or portion indicated) with the originator and send correct version. (To be used only at the discretion of, or by, the addressee to which the questioned message was directed.)	J
WAIT	I must pause for a few seconds	AS
WAIT – OUT	I must pause for longer than a few seconds.	AS AR
WILCO	I HAVE RECEIVED YOUR SIGNAL, UNDERSTAND IT, AND WILL COMPLY. To be used only by the addressee. Since the meaning of ROGER is included in that of WILCO, the two prowords are never used together.
WORD AFTER	The word of the message to which I have reference is that which follows…………..	WA
WORD BEFORE	The word of the message to which I have reference is that which precedes…………..	WB
WORDS TWICE	Communication is difficult. Transmit each phrase (or each code group) twice. (This proword may be used as an order, request, or as information.)	QSZ
WRONG	Your last transmission was incorrect. The correct version is…….	ZWF

Out of use

• Charlie charlie (confirmed, correct), still used in Africa by French pilots

See also

• NATO phonetic alphabet
• Ten-code
• Prosigns for Morse code

References

• FM 21-75