Ten-code


Ten-codes, officially known as ten signals, are brevity codes used to represent common phrases in voice communication, particularly by law enforcement and in Citizens Band 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, allow brevity and standardization of message traffic. They have historically been widely used by law enforcement officers in North America, but, due to the lack of standardization, in 2006 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:
  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,.
  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 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 standardization;
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, "Public Safety Standard Operating Procedures Manual", published as study cards in APCO Project 4, "Ten Signal Cards", and then revised in APCO Project 14.

In popular culture

Ten-codes, especially "10-4" first reached public recognition in the mid- to late-1950s through the popular television series Highway Patrol, with Broderick Crawford. Crawford would reach into his patrol car to use the microphone to answer a call and precede his response with "10-4".
Ten-codes were adapted for use by CB radio enthusiasts. C. W. McCall's hit song "Convoy", depicting conversation among CB-communicating truckers, put phrases like 10-4 and what's your twenty? into common use in American English.
The movie Convoy, loosely based on McCall's song, further entrenched ten-codes in casual conversation.
The ten-codes used by the New York Police Department have returned to public attention thanks to the popularity of the television series Blue Bloods. However, the ten-codes used by the NYPD are not the same as those used in the APCO system. For example, in the NYPD system, Code 10-13 means "Officer needs help," whereas in the APCO system "Officer needs help" is Code 10–33.
The New Zealand reality television show Police Ten 7 takes its name from the New Zealand Police ten-code 10–7, which means "Unit has arrived at job".
The syndicated internet radio countdown program "What's your Twenty" is named after the code for location.
A Facebook group named I'm 10-15 is allegedly used by some U.S. Customs and Border Protection employees. In July 2019, the group was reported to contain both racist, sexist discussions and caricature memes, along with threats against congresswomen scheduled to visit a Customs and Border Protection facility.

10-codes used for police officer retirement

Often when an officer retires a call to dispatch is made. The officer gives a 10-7 code and then a 10-42 code.

Official APCO Ten Signals by era

Replacement with plain language

While ten-codes were intended to be a terse, concise, and standardized system, the proliferation of different meanings can render them useless in situations when officers from different agencies and jurisdictions need to communicate.
In the fall of 2005, responding to inter-organizational communication problems during the rescue operations after Hurricane Katrina, the United States Federal Emergency Management Agency discouraged the use of ten-codes and other codes due to their wide variation in meaning. The Department of Homeland Security's SAFECOM program, established in response to communication problems experienced during the September 11 attacks also advises local agencies on how and why to transition to plain language, and their use is expressly forbidden in the nationally standardized Incident Command System, as is the use of other codes.
APCO International stated in 2012 that plain speech communications over public safety radio systems is preferred over the traditional 10-Codes and dispatch signals. Nineteen states had changed to plain English by the end of 2009., ten-codes remained in common use in many areas, but were increasingly being phased out in favor of plain language.

Clear Speech Procedure

In 1971, the Public Safety Department of Lakewood, Colorado published a study comparing the APCO Ten-code with the proposed Clear Speech procedure. The study used standards for judgment of both communications procedures based on The Public Safety Communications Standard Operating Procedure Manual, 1970 edition, published by APCO.
Was
Now
10-0Use Caution
10-1Unable to copy - change location
10-3Stop transmitting
10-4Roger
10-5Relay
10-6Busy
10-7Out at...
10-8Clear
10-9Say again
10-12Stand by
10-13Weather report/road report
10-15Disturbance
10-17ATheft
10-17BVandalism
10-17CShoplifting
10-18Urgent
10-19Return to...
10-20Location
10-21Call...
10-22Disregard
10-23On scene
10-25Meet...or contact...
10-26Detaining subject, expedite
10-27Drivers License information on...
10-28Registration information on...
10-29Check for wanted on...
10-31ABurglary
10-31BRobbery
10-31CHomicide
10-31DKidnapping
10-31EShooting
10-38Traffic stop on...
10-42Off duty
10-44Request for...
10-46Assist motorist
10-49East bound green light out
10-50Traffic
  • F=Fatal
  • PD=Property Damage
  • Hit and run
  • Injury
  • No injury reported
  • Unknown
  • Private property, location
10-56Drunk pedestrian
10-63Prepare to copy
10-70Fire
10-74Negative
10-76En route...
10-77ETA
10-78Request assistance
10-79Notify coroner
10-80Chase
10-89Bomb threat
10-90Alarm
10-91Pick up prisoner
10-92Parking complaint
10-95Prisoner in custody
10-97Check traffic signal
10-98Prison/jail break
10-99Wanted/stolen
  • Roger—To be used as acknowledgement.
  • AFFIRMATIVE—To be used when "yes" is needed
  • HELP—To be used when in danger and urgent assistance is needed.
    • CodeMeaning
    CODE ONEInforms all units to STANDBY - STOP TRANSMITTING. Do not transmit, except for emergency messages, while Code 1 is in effect. Dispatch shall announce, "Clear Code 1," when the condition is secured.
    CODE TWOIndicates an "urgent" call short of an "emergency" situation. A Code 2 call has priority over all other police activities except "emergencies".
    Proceed directly to Code 2 calls as quickly as is consistent with safety. Agents may, in exceptional cases, use their emergency equipment to traverse an otherwise clear intersection against a red traffic control device. Once clear of the intersection - turn off the emergency equipment.
    CODE THREEIndicates an EMERGENCY call. Red lights and siren are authorized. Proceed as quickly as possible with due regard for safety, and in compliance with the laws governing emergency vehicles.
    CODE FOURUsed to indicate that sufficient units have responded to a location, or that assistance is not needed, or is no longer needed.
    CODE FIVEUsed when Wanted/Records checks are requested by an agent to alert the agent of a wanted felon, a person known to be dangerous or a person known to be mentally unstable.
    A backup unit shall be dispatched Code 2 on all Code 5's.
    Personnel will NOT proceed with Code 5 details until the receiving unit requests some. The unit receiving a Code 5 will request the details when he is in a safe position to do so, which might not be until his backup arrives.
    CODE SIXWhen an agent is dispatched to a traffic accident, and the dispatcher states, "Code 6," the agent will advise the drivers involved to proceed to the station to file their reports. This will only be done if there are no injuries, no unusual circumstance and the vehicles are safely operable. Driver Exchange Forms will be completed at the scene to include the C. R. number.
    CODE SEVENIndicates "out of service - personal."
    CODE EIGHTAssist a fire department.

    Phrase Word Brevity Code

    About 1979, APCO created the Phrase Word Brevity Code as a direct replacement for the Ten-code.
    Phrase WordEnglish MeaningAPCO TEN CODE
    Use CautionCaution: dangerous condition is suspected to exist.10-0
    UnreadableRadio signal is too weak to receive.10-1
    Out of ServiceUnit, vehicle or person is not working10-7
    In ServiceUnit, vehicle or person is working but not necessarily "available" or "on radio."10-8
    AvailableUnit is in service ready to accept assignment, not necessarily by radio.10-24
    Not AvailableUnit cannot accept another assignment, but may be "on radio."10-7A
    Prepare to CopyDispatcher is about to give lengthy message.10-14
    Go AheadYou have been given clearance to transmit your message.- -
    Roger Message received and understood.10-4
    Say Again Repeat your message.10-9
    Stand ByStop transmitting and wait for further instructions.10-12
    Disregard Cancel your present assignment.10-22
    Off RadioUnit is not capable of being contacted by radio, but may be "available."10-7B
    On RadioUnit is capable of being contacted by radio, but not necessarily "available."10-11
    RespondingUnit is en route to assigned location.10-17
    Under ControlSituation is under control when no further assistance is anticipated.- -
    Telephone Call by telephone specified number or person.10-21
    PriorityWhen transmitted, means that the following transmission must have immediate attention.- -
    In PursuitUnit is chasing a vehicle and requires assistance from other units.- -
    Traffic StopUnit is going to stop a motorist.- -
    Help OfficerHelp me quick.10-33
    AffirmativeYes.10-4

    ICS Clear Text

    In 1980, the National Incident Management System published a document, ICS Clear Text Guide, which was another attempt to create a replacement for Ten-codes. The list of code words was republished in the 1990 Montana Mutual Aid and Common Frequencies document.
    Procedure WordMeaning
    UnreadableUsed when signal received is not clear. In most cases, try to add the specific trouble. Example: "Unreadable, background noise."
    Loud and ClearSelf-explanatory
    Stop TransmittingSelf-explanatory
    Copy, CopiesUsed to acknowledge message received. Unit radio identifier must also be used. Example: "Engine 2675, copies."
    AffirmativeYes
    NegativeNo
    Respond, RespondingUsed during dispatch - proceed to or proceeding to an incident. Example: "Engine 5176, respond..." or "St. Helena, Engine 1375 responding."
    EnrouteNormally used by administrative or staff personnel to designate destinations. Enroute is NOT a substitute for responding. Example: "Redding, Chief 2400 enroute RO II."
    In-quarters, with Station Name or NumberUsed to indicate that a units is in a station. Example: "Morgan Hill, Engine 4577 in-quarters, Sunol."
    UncoveredIndicates a unit is not in-service, because there are no personnel to operate it.
    Out-Of-ServiceIndicates a unit is mechanically out of service. Example: "Aburn, transport 2341, out-of-service." Note, when repairs have been completed the following phrase should be used: "Aburn transport 2341, back in-service, available."
    In-ServiceThis means that the unit is operating, not in response to a dispatch. Example: "Fortuna, Engine 1283, in-service, fire prevention inspections."
    RepeatSelf-explanatory
    WeatherSelf-explanatory
    Return toNormally used by communications center to direct units that are available to a station or other location.
    What is your Location?Self-explanatory
    Call ____ by PhoneSelf-explanatory
    Disregard Last MessageSelf-explanatory
    Stand-BySelf-explanatory
    Vehicle Registration CheckSelf-explanatory
    Is ____ Available for a Phone Call?Self-explanatory
    At SceneUsed when Units arrive at the scene of an incident. Example: "Perris, Engine 6183, at scene."
    Available at ResidenceUsed by administrative or staff personnel to indicate they are available and on-call at their residence.
    Can HandleUsed with the amount of equipment needed to handle the incident. Example: "Susanville Battalion 2212, can handle with units not at scene."
    Burning OperationsSelf-explanatory
    Report on ConditionsSelf-explanatory
    Fire under ControlSelf-explanatory
    Emergency Traffic OnlyRadio users will confine all radio transmissions to an emergency in progress or a new incident. Radio traffic which includes status information such as responding, reports on conditions, at scene and available will not be authorized during this period.
    Emergency TrafficTerm used to gain control of radio frequency to report an emergency. All other radio users will refrain from using that frequency until cleared for use by the communications center.
    Resume Normal TrafficSelf-explanatory

    Related codes

    Brevity codes other than the APCO 10-code are frequently used, and include several types: