The codes, developed in 1937 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, due to the lack of standardization, in 2006 the U.S. federal government recommended they be discontinued in favor of everyday language.
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.
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;
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).
In popular cultureEdit
Ten-codes, especially "10-4" (meaning "understood") 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" (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.
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, it must be noted that the ten-codes used by the NYPD are not the same as those used in the APCO system (see below). 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.
In the last episode of the anime "Kekkai Sensen & Beyond", Leonardo uses the code 10-33 in a message to signal that he is in a situation beyond his control.
Replacement with plain languageEdit
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 (FEMA) 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's current position states that plain speech communications over public safety radio systems is preferred over the traditional 10-Codes and dispatch signals, As of 2011[update], ten-codes remain in common use in many areas, but are increasingly being phased out in favor of plain language, with nineteen states planning to change to plain English as of the end of 2009[update].
Examples of U.S ten-codesEdit
Some examples of the codes are:
- 10-1 Bad reception
- 10-4 I acknowledge/Affirmative/Copy
- 10-7 Unit out of service
- 10-9 Say again
- 10-20 Advise to location
- 10-21 Call
- 10-33 Emergency: all units stand by
- 10-36 Correct time
Many additional codes have been added by individual local or regional first-response agencies; these are not standard across jurisdictions and may be problematic if multiple organizations must respond to the same incident.
Lists of APCO Ten SignalsEdit
|1937 APCO||1939 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
(plain language to replace Ten Codes)
|Phrase Word Brevity Code (c. 1979)|
|Procedure and Officer Details|
|10-1||Receiving poorly.||Receiving poorly||Unable to copy - change location||Signal Weak||Unable to copy - change location||Unreadable|
|10-2||Receiving well.||Receiving well||Signals good||Signal Good||—|
|10-3||Stop transmitting.||Disregard last information||Stop transmitting||Stop Transmitting||Stop transmitting|
|10-4||Acknowledgement.||Message received||Acknowledgement||Affirmative (Ok)||Roger||Roger/Affirmative|
|10-6||Busy.||Busy, stand by||Busy -Stand by unless urgent||Busy||Busy|
|10-7||Out of service.||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||In service||In Service||Clear||In Service|
|10-9||Repeat, conditions bad.||Repeat||Repeat||Say Again||Say again||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.||We have prisoner in custody||Civil disturbance||Message Delivered||Disturbance|
|10-16||Pick up prisoner at ...||Pick up prisoner at||Domestic trouble||Reply to Message||—|
|10-17||Pick up papers at ...||Pick up papers at||Meet complainant||Enroute||—||Responding|
|10-18||Complete present assignment as quickly as possible.||Anything for us?||Complete assignment quickly||Urgent||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 telephone||Call (...) by Phone||Call ...||Telephone|
|10-22||Take no further action last information.||Report in person to ...||Disregard||Disregard||Disregard||Disregard|
|10-23||Stand by until no interference cause to Iowa (Mo.) etc.||Arrived at scene||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.||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||—|
|10-32||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, blocade||Major crime alert||—Reserved—||—|
|10-36||Correct time?||—||Correct time||—Reserved—||—|
|10-37||Operator on duty?||No rush||Investigate suspicious vehicle||—Reserved—||—|
|10-38||Station report--satisfactory.||Hurry, but do not use red light or siren||Stopping suspicious vehicle (Give station complete description before stopping).||—Reserved—||Traffic stop on ...|
|10-39||Your Nr...delivered to addressee.||Use red light and siren||Urgent-Use light and siren||—Reserved—||—|
|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)
|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||—|
|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||—|
|10-75||—||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.||—||Pick up checks for distribution||—|
|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|
|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|
Clear Speech Procedure Words and CodesEdit
|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.|
|CODE ONE||Informs 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 TWO||Indicates 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 (both visual and audible to comply with state law) to transverse an otherwise clear intersection against a red traffic control device. Once clear of the intersection - turn off the emergency equipment.
|CODE THREE||Indicates 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 FOUR||Used to indicate that sufficient units have responded to a location, or that assistance is not needed, or is no longer needed.|
|CODE FIVE||Used 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 same. 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 SIX||When 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 situation 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 SEVEN||Indicates "out of service - personal."|
|CODE EIGHT||Assist a fire department.|
- The California Highway Patrol uses ten-codes, along with an additional set of eleven- and higher codes.
- California Penal Code sections were in use by the Los Angeles Police Department as early as the 1940s, and these Hundred Code numbers are still used today instead of the corresponding ten-code. Generally these are given as two sets of numbers—"One Eighty-Seven" or "Fifty-One Fifty"—with a few exceptions such as "459"—Burglary, which is given as "Four-Five-Nine". The American public was made aware of these California Penal Code references as a result of the TV series Adam-12, which used them habitually in radio communications and in the main title of the show. The best-known include:
- "187": Homicide
- "211": Robbery
- "415": Disturbance
- "417": Person with a weapon
- "502": Intoxicated Driver
- "5150": Mentally disturbed person (actually a reference to the California Welfare and Institutions Code)
- The New York Fire Department uses its own ten-code system.
- The New Zealand Fire Service uses a system of "K-codes" to pass fire appliance availability statuses as well as operational messages. For example, "K1" means "proceeding to incident", while "K99" means "Structure fire, well involved". The New Zealand Police also use some K-codes, with completely unrelated meanings to those used by NZFS; Police code "K1" means "no further police action required".
- Telegraph and teletype procedures
- Q code and prosigns for Morse code are used in amateur radio, aviation and marine radio. They provide specific abbreviations for concepts related to aviation, shipping, RTTY, radiotelegraph and amateur radio. In radiotelegraph operation, a Q code is often shorter (as ten-codes require transmission of three prefix characters: 1, 0, hyphen) and provides standardization of codes, essential in international and shortwave communications.
- Z codes are used by NATO countries in military radio communications.
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- "Ten Code Versus Clear Speech Communication" (PDF). Archived from the original on 2006-03-13.
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- Official Ten-Code List Association of Public Communications Officers (APCO)