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Voice procedure includes various techniques used to clarify, simplify and standardize spoken communications over two-way radios, in use by the military, in civil aviation, police and fire dispatching systems, citizens' band radio (CB), etc.
Voice procedure communications are intended to maximize clarity of spoken communication and reduce misunderstanding. It consists of signalling protocol such as the use of abbreviated codes like the CB radio ten-code, Q codes in amateur radio and aviation, police codes, etc., and jargon.
Some elements of voice procedure are understood across many applications, but significant variations exist. The military of the NATO countries have similar procedures in order to make cooperation easier, and pseudo-military organizations often base their procedures on them, so some commonality exists there. On the other hand, some elements of police codes are not necessarily standardized even within the same jurisdiction, and using the less familiar codes can defeat the purpose of good communication.
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Words in voice procedure
Some words with specialized meanings are used in radio communication throughout the English-speaking world, and in international radio communications, where English is the lingua franca.
- Affirmative — Yes
- Negative — No
- Over — I have finished talking and I am listening for your reply. Short for "Over to you."
- Out or Clear — I have finished talking to you and do not expect a reply.
- Roger — Information received.
- Copy — I understand what you just said (after receiving information).
- Wilco — Will comply (after receiving new directions). Implies "roger".
- Go ahead or Send your traffic — Send your transmission.
- Say again — Please repeat your last message (Repeat is not used as it is a specific command when calling for artillery fire)
- Sécurité — Maritime safety call. Repeated three times. Has priority over routine calls.
- Pan-pan — Maritime urgency call. Repeated three times. Has priority over safety calls.
- Mayday — Maritime distress call. Repeated three times and at beginning of every following transmission relating to the current distress situation. Has priority over urgency and safety calls.
"Roger" was the U.S. military designation for the letter R (as in received) from 1927 to 1957.[1]
The phrases "over" and "out" are generally only used on maritime radios since there are usually far fewer transmissions. Air traffic control (aviation) radio communications, on the other hand, are usually very busy, particularly in the airport environment. The terms "over" and "out" are never used on air traffic control (aviation) radio communications in the interest of "com brevity".
Example usage
The Federal Aviation Administration uses the term phraseology to describe voice procedure or communications protocols used over telecommunications circuits. An example is air traffic control radio communications. Standardized wording is used and the person receiving the message may repeat critical parts of the message back to the sender. This is especially true of safety-critical messages.[2] Consider this example of an exchange between a controller and an aircraft:
Aircraft: Boston Tower, Warrior tree fife foxtrot, holding short of one eight left.
Tower: Tree fife foxtrot, Boston Tower, runway one eight left, cleared for immediate takeoff.
Aircraft: Roger, tree fife foxtrot, cleared for immediate takeoff, one eight left.
On telecommunications circuits, disambiguation is a critical function of voice procedure. Due to any number of variables, including radio static, a busy or loud environment, or similarity in the phonetics of different words, a critical piece of information can be misheard or misunderstood; for instance, a pilot being ordered to eleven thousand as opposed to seven thousand. To reduce ambiguity, critical information may be broken down and read as separate letters and numbers. To avoid error or misunderstanding, pilots will often read back altitudes in the tens of thousands using both separate numbers and the single word (example: given a climb to 10,000 ft, the pilot replies "[Callsign] climbing to One zero, Ten Thousand"). However, this is usually only used to differentiate between 10,000 and 11,000 ft since these are the most common altitude deviations. The runway number read visually as eighteen, when read over a voice circuit as part of an instruction, becomes one eight. In some cases a spelling alphabet is used (also called a radio alphabet or a phonetic alphabet) . Instead of the letters AB, the words Alpha Bravo are used. Main Street becomes Mike Alpha India November street, clearly separating it from Drain Street and Wayne Street. The numbers 5 and 9 are pronounced "fife" and "niner" respectively, since "five" and "nine" can sound the same over the radio.
Over fire service radios, phraseology may include words that indicate the priority of a message, for example:[3]
Ladder Forty Four to Manhattan, Urgent!
or
San Diego, Engine Forty, Emergency traffic!
Words may be repeated to modify them from traditional use in order to a describe a critical message:[4]
Evacuate! Evacuate! Evacuate!
Police Radios also use this technique to escalate a call that is quickly becoming an emergency.
Code 3! Code 3! Code 3!
Railroads have similar processes. When instructions are read to a locomotive engineer, they are preceded by the engineer's name, direction of travel, and the train or locomotive number. This reduces the possibility that a set of instructions will be acted on by the wrong locomotive engineer:
Five Sixty Six West, Engineer Jones, okay to proceed two blocks west to Ravendale.
Phraseology on telecommunications circuits may employ special phrases like ten codes, Sigalert, Quick Alert! or road service towing abbreviations such as T6. This jargon may abbreviate critical data and alert listeners by identifying the priority of a message. It may also reduce errors caused by ambiguities involving rhyming, or similar-sounding, words.
Maritime procedure
Boat "Albacore" talking to Boat "Bronwyn"
Albacore: Bronwyn, Bronwyn, Bronwyn this is Albacore, message, over.
Bronwyn: Albacore. send over
Albacore: Bronwyn. Want a tow and are you ok for tea at Osbourne Bay? over.
Bronwyn: Albacore. no thanks, got engine running, 1600 at clubhouse fine with us. over
Albacore: Bronwyn. ok, out.
The advantage of this sequence is that the recipient always knows for whom the message was intended.
This system works better than British Army when the message rate and signal quality is low.
British Army
Station C21(charlie-two-one) talking to C33(charlie-three-three):
C21: Hello C33 this is C21 over.
C33: C33 over.
C21: have you got Sunray C10 at your location? over.
C33: no, I think he is with C30. over.
C21: ok, out.
The advantage of this sequence is that the recipient always knows who sent the message.
The downside is that the listener only knows the intended recipient from the context of the conversation. Requires moderate signal quality for the radio operator to keep track of the conversations.
However a broadcast message and response is fairly efficient.
0: Hello all stations, this is 0. Radio check. over.
1: 1. ok. over.
2: 2. ok. over.
3: 3. difficult. over.
4: 4. ok. over.
0: 0. ok all stations, 3 difficult. out.
Control
Voice protocols also cover who can speak on a frequency and when. A controlled frequency (or controlled net) is controlled by one station and any parties wishing to use the frequency must direct all calls to the control station. A tactical frequency (or tactical net) has no control station.
Notes
- ^ SDSTAFF Robin (2007-02-27). "Why do pilots say "roger" on the radio?". The Straight Dope. http://web.archive.org/web/20080129171204/http://www.straightdope.com/mailbag/mroger.htm.
- ^ See: "Section 2: Radio Communications Phraseology and Techniques," Aeronautical Information Manual, US Department of Transportation, Federal Aviation Administration. Any year AIM will serve as an example. Another example is "Completing the Loop: Two-Way Communication," Special Report: Improving Firefighter Communications, USFA-TR-099/January 1999, (Emmitsburg, Maryland: U.S. Fire Administration, 1999) pp. 27.
- ^ See, "Problem Reporting," Special Report: Improving Firefighter Communications, USFA-TR-099/January 1999, (Emmitsburg, Maryland: U.S. Fire Administration, 1999) pp. 25-26. FDNY has implemented these ideas and they were observed on publicly-released FDNY 9-11-01 logging recorder audio CDs. Portions of these CDs were broadcast on news programs.
- ^ For an example of fire procedures, look at "Communications Procedures," XII-A-4.JH.970314, (Los Gatos, California, Santa Clara County Fire Department, Training Division, 03/14/1997).
See also
External links
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