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.
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.
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.
In August 1935, the APCO Bulletin published a recommendation that the organization issue a handbook that described standard operating procedures, including: A standard message form for use by all police departments. A simple code for service dispatches relating to corrections, repetitions, etc. 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). A standard record system for logging the operation of the station. 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 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. 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.http://28011b0082f55a9e1ec0-aecfa82ae628504f4b1d229bd9030ae1.r13.cf1.rackcdn.com/1940-01-p008-200.pdf , p.8
In 1954, APCO published an article describing a proposed simplification of the code, based on an analysis conducted by the San Diego Police Department. In the September 1955 issue of the APCO Bulletin, a revision of the Ten-Signals was proposed, 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).9-Code, 10-Code. Dispatch Magazine online.
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.
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.
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".
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).
Signals by time period (North America) Signal APCO Meaning1937 APCO1939 First Published Set (17 signals)1940 (APCO Standards Committee)1955 (National Operating Procedure Committee)APCO Project 2 (1967)APCO Project 4 (1973)APCO Project 14 (1974)Clear Speech (c. 1971)
(plain language to replace Ten Codes)Phrase Word Brevity Code (c. 1979)Procedure and Officer Details10-MAXAWOL - - -Corrupt OfficerOfficer not following ordersInsubordination/Rogue OfficerGo AheadUnder ControlIn PursuitTraffic Stop10-0————Use caution10-1Receiving poorly.Unable to copy - change locationSignal WeakUnable to copy - change locationUnreadable10-2Receiving well.Signals goodSignal Good—10-3Stop transmitting.Disregard last informationStop transmittingStop Transmitting10-4Acknowledgement.Message receivedAcknowledgementAffirmative (Ok)RogerRoger/Affirmative10-5Relay.Relay (To)Relay10-6Busy.Busy, stand byBusy -Stand by unless urgentBusyBusy10-7Out of service.Out of service (Give location and/or telephone number)Out of ServiceOut at ...Out of Service10-7 A—Not Available10-7 BOff Radio10-8In service.In ServiceClearIn Service10-9Repeat, conditions bad.RepeatSay Again10-10Out of service—subject to call.On minor detail, subject to callFight in progressNegative—10-11Dispatching too rapidly.Stay in serviceDog Case... On DutyOn Radio10-12Officials or visitors present.Visitors or officials presentStand by (stop)Stand By (Stop)Stand byStand By10-13Advise weather and road conditions.Weather and road conditionsWeather and road reportExisting ConditionsWeather report/road report10-14Convoy or escort.Convoy or escortReport of prowlerMessage/Information—Prepare to Copy10-15We have prisoner in custody.Civil disturbanceMessage DeliveredDisturbance10-16Pick up prisoner at ...Domestic troubleReply to Message—10-17Pick up papers at ...Meet complainantEnrouteResponding10-17 A————Theft10-17 BVandalism10-17 CShoplifting10-18Complete present assignment as quickly as possible.Anything for us?Complete assignment quicklyUrgentPriority10-19Return to your station.Nothing for youReturn to ...(In) ContactReturn to ...10-20What is your location?LocationLocationLocationLocation10-21Call this station by telephone.Call ... by phoneCall (...) by PhoneCall ...Telephone10-22Take no further action last information.Report in person to ...DisregardDisregard10-23Stand by until no interference.Arrived at sceneArrived at SceneOn scene10-24Trouble at station—unwelcome visitors—all units vicinity report at once.Finished with last assignmentAssignment completedAssignment Completed—Available10-25Do you have contact with...?Operator or officer on duty?Report in person to (meet) ...Report to (Meet) ...Meet ... or contact ...10-26Can you obtain automobile registration information?Holding subject, rush replyDetaining subject, expediteEstimated Arrival TimeDetaining subject, expedite10-27Any answer our number...?Request driver's license informationDrivers license informationLicense/Permit InformationDrivers license information on ...10-28Check full registration information.Request full registration informationVehicle registration informationOwnership InformationRegistration information on ...10-29Check for wanted.Check record for wantedCheck records for wanted.Records CheckCheck for wanted on ...Emergency or Unusual10-30Does not conform to rules and regulations.Illegal use of radioDanger/Caution—Use Caution10-31Is lie detector available?Emergency basis, all squads, 10-11Crime in progressPick Up—10-31 A————Burglary10-31 BRobbery10-31 CHomicide10-31 DKidnapping10-31 EShooting10-32Is drunkometer available?Chase, all squads stand byMan with gun... Units Needed (Specify)—10-33Emergency traffic at this station—clear?Emergency traffic this stationEMERGENCYHelp Me QuickHelp Officer10-34Clear for local dispatch?Trouble at station, assistance neededRiotTime10-35Confidential information.Major crime, blockadeMajor crime alert—Reserved—10-36Correct time?—Correct time10-37Operator on duty?No rushInvestigate suspicious vehicle10-38Station report—satisfactory.Hurry, but do not use red light or sirenStopping suspicious vehicle (Give station complete description before stopping).Traffic stop on ...10-39Your Nr...delivered to addressee.Use red light and sirenUrgent-Use light and siren—General UsePrivate Use10-40Advise if Officer...available for radio call.NotificationSilent run - No light or siren—10-41Tune to ... kcs. for test with mobile unit or emergency service.Car change at ...Beginning tour of duty10-42—Crew change at ...Ending tour of dutyOff duty10-43Take school crossingInformation—10-44—Request permission to leave patrol ... for ...Request for ...10-45Animal carcass in ... lane at ...—10-46Assist motoristAssist motorist10-47Emergency road repairs needed—10-48Traffic standard needs repairs10-49Hourly report markTraffic light outEast bound green light out (etc.)Accident and Vehicle Handling10-50—Auto accident, property damage onlyAccident—F, PI, PDTraffic (F, PD) Traffic
Hit and run Injury No injury reported Unknown