Ten-code

"10-1" redirects here. For the FIFA World Cup match, see Hungary v El Salvador (1982 FIFA World Cup).

"10-20" redirects here. For the EEG electrode placement system, see 10–20 system (EEG).

Ten-codes, officially known as ten signals, are brevity codes used to represent common phrases in voice communication, particularly by US public safety officials and in citizens band (CB) radio transmissions. The police version of ten-codes is officially known as the APCO Project 14 Aural Brevity Code.^[1]

The codes, developed during 1937–1940 and expanded in 1974 by the Association of Public-Safety Communications Officials-International (APCO), allow brevity and standardization of message traffic. They have historically been widely used by law enforcement officers in North America, but in 2006, due to the lack of standardization, the U.S. federal government recommended they be discontinued in favor of everyday language.^[2]

History

APCO first proposed Morse code brevity codes in the June 1935 issue of The APCO Bulletin, which were adapted from the procedure symbols of the U.S. Navy, though these procedures were for communications in Morse code, not voice.^[3]

In August 1935, the APCO Bulletin published a recommendation that the organization issue a handbook that described standard operating procedures, including:^[4]

1. A standard message form for use by all police departments.
2. A simple code for service dispatches relating to corrections, repetitions, etc.
3. A standard arrangement of the context of messages, (for example, name and description of missing person might be transmitted as follows: Name, age, height, weight, physical characteristics, clothing; if car used, the license, make, description and motor number. This information would actually be transmitted in the text of the message as follows: John Brown 28-5-9-165 medium build brown eyes dark hair dark suit light hat Mich. 35 lic. W 2605 Ford S 35 blue red wheels 2345678 may go to Indiana).
4. A standard record system for logging the operation of the station.
5. Other important records in accordance with the uniform crime reporting system sponsored by the International Association of Chiefs of Police.

The development of the APCO Ten Signals began in 1937^[5] to reduce use of speech on the radio at a time when police radio channels were limited. Credit for inventing the codes goes to Charles "Charlie" Hopper, communications director for the Illinois State Police, District 10 in Pesotum, Illinois. Hopper had been involved in radio for years and realized there was a need to abbreviate transmissions on State Police bands.^[6] Experienced radio operators knew the first syllable of a transmission was frequently not understood because of quirks in early electronics technology. Radios in the 1930s were based on vacuum tubes powered by a small motor-generator called a dynamotor. The dynamotor took from 1/10 to 1/4 of a second to "spin up" to full power. Police officers were trained to push the microphone button, then pause briefly before speaking; however, sometimes they would forget to wait. Preceding each code with "ten-" gave the radio transmitter time to reach full power. An APCO Bulletin of January 1940 lists codes assigned as part of standardisation.^[7]

In 1954, APCO published an article describing a proposed simplification of the code, based on an analysis conducted by the San Diego Police Department.^[8] In the September 1955 issue of the APCO Bulletin, a revision of the Ten-Signals was proposed,^[9] and it was later adopted.

The Ten Signals were included in APCO Project Two (1967), "Public Safety Standard Operating Procedures Manual", published as study cards in APCO Project 4 (1973), "Ten Signal Cards", and then revised in APCO Project 14 (1974).^{[10][11][12][13]}

In popular culture

Ten-codes, especially "10-4" (meaning "understood") first reached public recognition in the mid- to late-1950s through the television series Highway Patrol, with Broderick Crawford.^{[citation needed]}

Ten-codes were adapted for use by CB radio enthusiasts. C. W. McCall's hit song "Convoy" (1975), depicting conversation among CB-communicating truckers, put phrases like "10-4" and "what's your twenty?" (10-20 for "where are you?") into common use in American English.^{[citation needed]}

The movie Convoy (1978), loosely based on McCall's song, further entrenched ten-codes in casual conversation, as did the movie Smokey and the Bandit.

The New Zealand reality television show Ten 7 Aotearoa (formerly Police Ten 7) takes its name from the New Zealand Police ten-code 10-7, which means "Unit has arrived at job".^[14][15]

Police officer retirement (North America)

Often when an officer retires, a call to dispatch is made. The officer gives a 10-7 code (Out of service) and then a 10-42 code (ending tour of duty).^[16][17]

Signals by era (North America)

Signal			APCO Meaning
	1937 APCO	1939 First Published Set (17 signals)[18]	1940 (APCO Standards Committee)[19][20]	1955 (National Operating Procedure Committee)[21]	APCO Project 2 (1967)[22]	APCO Project 4 (1973)	APCO Project 14 (1974)[23][24]	Clear Speech (c. 1971) (plain language to replace Ten Codes)[25]	Phrase Word Brevity Code (c. 1979)[26]
Procedure and Officer Details
10-MAX		AWOL	-	-	-		Corrupt Officer	Officer not following orders	Insubord­ination/​Rogue Officer
									Go Ahead
									Under Control
									In Pursuit
									Traffic Stop
10-0			—	—	—		—	Use caution
10-1			Receiving poorly.		Unable to copy - change location		Signal Weak	Unable to copy - change location	Unreadable
10-2			Receiving well.		Signals good		Signal Good	—
10-3			Stop transmitting.	Disregard last information	Stop transmitting		Stop Transmitting
10-4			Acknowl­edgement.	Message received	Acknowl­edgement		Affirmative (Ok)	Roger	Roger/​Affirmative
10-5			Relay.				Relay (To)	Relay
10-6			Busy.	Busy, stand by	Busy -Stand by unless urgent		Busy	Busy
10-7			Out of service.		Out of service (Give location and/or telephone number)		Out of Service	Out at ...	Out of Service
10-7 A							—		Not Available
10-7 B									Off Radio
10-8			In service.				In Service	Clear	In Service
10-9			Repeat, conditions bad.	Repeat			Say Again
10-10			Out of service—subject to call.	On minor detail, subject to call	Fight in progress		Negative	—
10-11			Dispatching too rapidly.	Stay in service	Dog Case		... On Duty		On Radio
10-12			Officials or visitors present.	Visitors or officials present	Stand by (stop)		Stand By (Stop)	Stand by	Stand By
10-13			Advise weather and road conditions.	Weather and road conditions	Weather and road report		Existing Conditions	Weather report/​road report
10-14			Convoy or escort.	Convoy or escort	Report of prowler		Message/​Information	—	Prepare to Copy
10-15			We have prisoner in custody.		Civil disturbance		Message Delivered	Disturbance
10-16			Pick up prisoner at ...		Domestic trouble		Reply to Message	—
10-17			Pick up papers at ...		Meet complainant		Enroute		Responding
10-17 A			—	—	—		—	Theft
10-17 B								Vandalism
10-17 C								Shoplifting
10-18			Complete present assignment as quickly as possible.	Anything for us?	Complete assignment quickly		Urgent		Priority
10-19			Return to your station.	Nothing for you	Return to ...		(In) Contact	Return to ...
10-20			What is your location?	Location	Location		Location	Location
10-21			Call this station by telephone.	Call ... by phone			Call (...) by Phone	Call ...	Telephone
10-22			Take no further action last information.	Report in person to ...	Disregard		Disregard
10-23			Stand by until no interference.	Arrived at scene			Arrived at Scene	On scene
10-24			Trouble at station—unwelcome visitors—all units vicinity report at once.	Finished with last assignment	Assignment completed		Assignment Completed	—	Available
10-25			Do you have contact with...?	Operator or officer on duty?	Report in person to (meet) ...		Report to (Meet) ...	Meet ... or contact ...
10-26			Can you obtain automobile registration information?	Holding subject, rush reply	Detaining subject, expedite		Estimated Arrival Time	Detaining subject, expedite
10-27			Any answer our number...?	Request driver's license information	Drivers license information		License/​Permit Information	Drivers license information on ...
10-28			Check full registration information.	Request full registration information	Vehicle registration information		Ownership Information	Registration information on ...
10-29			Check for wanted.	Check record for wanted	Check records for wanted.		Records Check	Check for wanted on ...
Emergency or Unusual
10-30			Does not conform to rules and regulations.		Illegal use of radio		Danger/​Caution	—	Use Caution
10-31			Is lie detector available?	Emergency basis, all squads, 10-11	Crime in progress		Pick Up	—
10-31 A			—	—	—		—	Burglary
10-31 B								Robbery
10-31 C								Homicide
10-31 D								Kidnapping
10-31 E								Shooting
10-32			Is drunkometer available?	Chase, all squads stand by	Man with gun		... Units Needed (Specify)	—
10-33			Emergency traffic at this station—clear?	Emergency traffic this station	EMERGENCY		Help Me Quick		Help Officer
10-34			Clear for local dispatch?	Trouble at station, assistance needed	Riot		Time
10-35			Confidential information.	Major crime, blockade	Major crime alert		—Reserved—
10-36			Correct time?	—	Correct time
10-37			Operator on duty?	No rush	Investigate suspicious vehicle
10-38			Station report—satisfactory.	Hurry, but do not use red light or siren	Stopping suspicious vehicle (Give station complete description before stopping).			Traffic stop on ...
10-39			Your Nr...delivered to addressee.	Use red light and siren	Urgent-Use light and siren			—
General Use							Private Use
10-40			Advise if Officer...available for radio call.	Notification	Silent run - No light or siren			—
10-41			Tune to ... kcs. for test with mobile unit or emergency service.	Car change at ...	Beginning tour of duty
10-42			—	Crew change at ...	Ending tour of duty			Off duty
10-43				Take school crossing	Information			—
10-44				—	Request permission to leave patrol ... for ...			Request for ...
10-45					Animal carcass in ... lane at ...			—
10-46					Assist motorist			Assist motorist
10-47					Emergency road repairs needed			—
10-48					Traffic standard needs repairs
10-49				Hourly report mark	Traffic light out			East bound green light out (etc.)
Accident and Vehicle Handling
10-50			—	Auto accident, property damage only	Accident—F, PI, PD			Traffic (F, PD) Traffic Hit and run Injury No injury reported Unknown Private property, location
10-51				Auto accident, wrecker sent	Wrecker needed			—
10-52				Auto accident, personal injuries, ambulance sent	Ambulance needed
10-53				Auto accident, fatal	Road blocked
10-54				—	Livestock on highway
10-55				Drunken driver	Intoxicated driver
10-56				—	Intoxicated pedestrian			Drunk pedestrian
10-57				—	Hit and run—F, PI, PD			—
10-58				Is wrecker on the way?	Direct traffic
10-59				Is ambulance on the way?	Convoy or escort
Net Message Handling
10-60			What is next item (message) number?	What is your next message number?	Squad in vicinity			—
10-61			Stand by for CW traffic on ... kcs.	CW traffic	Personnel in area.
10-62			Unable to copy phone—use CW.	Any answer our Nr. ...	Reply to message
10-63			Net directed.	Time	Prepare to make written copy			Prepare to copy
10-64			Net free.	—	Message for local delivery			—
10-65			Clear for item (message) assignment?	Clear for message assignment	Net message assignment
10-66			Clear for cancellation?	Clear for cancellation	Message cancellation
10-67			Stations...carry this item (message).	Clear for net message	Clear to read net message
10-68			Repeat dispatch.	—	Dispatch information
10-69			Have you dispatched...?		Message received
Fire
10-70			Net message (State net traffic).	Fire, phone alarm	Fire alarm			Fire
10-71			Proceed with traffic in sequence (busy here).	Box alarm	Advise nature of fire (size, type, and contents of building)			—
10-72			—	Second alarm	Report progress on fire
10-73				Third alarm	Smoke report
10-74				Fourth alarm	Negative			Negative
10-75				Fifth alarm	In contact with			—
10-76				Fire equipment needed	En Route			En route ...
10-77				Fire, grass	ETA (Estimated Time of Arrival)			ETA (Estimated time of arrival)
10-78				Set up command post	Need assistance			Request Assistance
10-79				Report progress on fire	Notify coroner			Notify coroner (to be done by phone whenever possible)
The 80 series is reserved for assignment by nets for local use.				Personal Favors	—
10-80			... tower lights at this station burned out.	—	—			Chase
10-81			Officer Nr. ... will be at your station ...					—
10-82			Reserve room with bath at hotel for officer Nr. ...	Reserve hotel room	Reserve lodging
10-83			Have officer Nr. ... call this station by telephone.	—	—
10-84			Advise telephone Nr. ... your city that officer Nr. ... will not return this date.		If meeting ... advise ETA
10-85			Officer ... left this station for ... (Jefferson City) (Des Moines) at ...		Will be late
10-86			Officer ... left this station for ... at ...		—
10-87			Officer Nr. ... will be in ... if officer Nr. ... will be in.		Meet the officer at ______.
10-88			What phone number shall we call to make station to station call to officer Nr. ...?	Advise phone number for station to station call	Advise present telephone number of ...
10-89			Request radio service man be sent to this station...	Radio transmission	—			Bomb threat
Technical
10-90			Radio service man will be at your station ....	Transmit on alternate frequency	Bank alarm			Alarm (type of alarm)
10-91			Prepare for inspection (date) ... (time) ...	—	Unnecessary use of radio			Pick up prisoner
10-92			Your quality poor—transmitter apparently out of adjustment.		—			Parking complaint
10-93			Frequencies to be checked this date.	Frequency check	Blockade			—
10-94			Test—no modulation—for frequency check.	Give me a test	Drag racing
10-95			Test intermittently with normal modulation for ...	—	—			Prisoner in custody
10-96			Test continuously with tone modulation for ...		Mental subject			—
10-97			—		—			Check traffic signal
10-98					Prison or jail break			Prison/jail break
10-99					Records indicate wanted or stolen			Wanted/​stolen

Usage by Areas

New Zealand

The New Zealand Police use a variety of radio communication codes including its own version of 10-codes seen below.^[27]

Code	Meaning	Activity
10-0	Off duty	In use
10-1	Broadcast to all units	In use
10-2	Enroute to job/event	In use
10-3	Available	In use
10-4	Repeat your last message	In use
10-5	Out of service for a short time	Not in use
10-6	Change radio channel	In use
10-8	Arrived at job/event	In use
10-9	Busy but Available	In use
10-10	Officer requires immediate assistance (call for help)	In use

Philippines