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.
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).
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)
{| class="wikitable"
!Signal
!
!
! colspan=5 | APCO Meaning
!
!
|-
!
!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
(c. 1971)
(plain language to replace Ten Codes)
!Phrase Word Brevity Code (c. 1979)
|-
| colspan="9" |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
|
|
| colspan="2" |Receiving poorly.
|Unable to copy - change location
|
|Signal Weak
|Unable to copy - change location
|Unreadable
|-
|10-2
|
|
| colspan="2" |Receiving well.
|Signals good
|
|Signal Good
|—
|
|-
|10-3
|
|
|Stop transmitting.
|Disregard last information
|Stop transmitting
|
| colspan="2" |Stop Transmitting
|
|-
|10-4
|
|
|Acknowledgement.
|Message received
|Acknowledgement
|
|Affirmative (Ok)
|Roger
|Roger/Affirmative
|-
|10-5
|
|
| colspan="3" |Relay.
|
|Relay (To)
|Relay
|
|-
|10-6
|
|
|Busy.
|Busy, stand by
|Busy -Stand by unless urgent
|
|Busy
|Busy
|
|-
|10-7
|
|
| colspan="2" |Out of service.
|Out of service (Give location and/or telephone number)
|
|Out of Service
|Out at ...
|Out of Service
|-
|10-7 A
|
|
|
|
|
|
| rowspan="2" |—
|
|Not Available
|-
|10-7 B
|
|
|
|
|
|
|
|Off Radio
|-
|10-8
|
|
| colspan="3" |In service.
|
|In Service
|Clear
|In Service
|-
|10-9
|
|
|Repeat, conditions bad.
| colspan="2" |Repeat
|
| colspan="3" |Say Again
|-
|10-10
|
|
|Out of service—subject to call.
|On minor detail, subject to call
|Fight in progress
|
|Negative
| rowspan="2" |—
|
|-
|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
|
|
| colspan="2" |We have prisoner in custody.
|Civil disturbance
|
|Message Delivered
|Disturbance
|
|-
|10-16
|
|
| colspan="2" |Pick up prisoner at ...
|Domestic trouble
|
|Reply to Message
| rowspan="2" |—
|
|-
|10-17
|
|
| colspan="2" |Pick up papers at ...
|Meet complainant
|
|Enroute
|Responding
|-
|10-17 A
|
|
| rowspan="3" |—
| rowspan="3" |—
| rowspan="3" |—
|
| rowspan="3" |—
|Theft
|
|-
|10-17 B
|
|
|
|Vandalism
|
|-
|10-17 C
|
|
|
|Shoplifting
|
|-
|10-18
|
|
|Complete present assignment as quickly as possible.
|Anything for us?
|Complete assignment quickly
|
| colspan="2" |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.
| colspan="2" |Call ... by phone
|
|Call (...) by Phone
|Call ...
|Telephone
|-
|10-22
|
|
|Take no further action last information.
|Report in person to ...
|Disregard
|
| colspan="3" |Disregard
|-
|10-23
|
|
|Stand by until no interference.
| colspan="2" |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 ...
|
|-
| colspan="9" |Emergency or Unusual
|
|-
|10-30
|
|
| colspan="2" |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
|
|
| rowspan="5" |—
| rowspan="5" |—
| rowspan="5" |—
|
| rowspan="5" |—
|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)
| rowspan="6" |—
|
|-
|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
|
| rowspan="5" |—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
|
|—
|
|-
| colspan="7" |General Use
|Private Use
|
|
|-
|10-40
|
|
|Advise if Officer...available for radio call.
|Notification
|Silent run - No light or siren
|
|
| rowspan="2" |—
|
|-
|10-41
|
|
|Tune to ... kcs. for test with mobile unit or emergency service.
|Car change at ...
|Beginning tour of duty
|
|
|
|-
|10-42
|
|
| rowspan="8" |—
|Crew change at ...
|Ending tour of duty
|
|
|Off duty
|
|-
|10-43
|
|
|Take school crossing
|Information
|
|
|—
|
|-
|10-44
|
|
| rowspan="5" |—
|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
|
|
| rowspan="2" |—
|
|-
|10-48
|
|
|Traffic standard needs repairs
|
|
|
|-
|10-49
|
|
|Hourly report mark
|Traffic light out
|
|
|East bound green light out (etc.)
|
|-
| colspan="9" |Accident and Vehicle Handling
|
|-
|10-50
|
|
| rowspan="10" |—
|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
|
|
| rowspan="5" |—
|
|-
|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
|
|
| rowspan="3" |—
|
|-
|10-58
|
|
|Is wrecker on the way?
|Direct traffic
|
|
|
|-
|10-59
|
|
|Is ambulance on the way?
|Convoy or escort
|
|
|
|-
| colspan="9" |Net Message Handling
|
|-
|10-60
|
|
|What is next item (message) number?
|What is your next message number?
|Squad in vicinity
|
|
| rowspan="3" |—
|
|-
|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
|
|
| rowspan="6" |—
|
|-
|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.
| rowspan="2" |—
|Dispatch information
|
|
|
|-
|10-69
|
|
|Have you dispatched...?
|Message received
|
|
|
|-
| colspan="9" |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)
|
|
| rowspan="3" |—
|
|-
|10-72
|
|
| rowspan="8" |—
|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)
|
|-
| colspan="4" |The 80 series is reserved for assignment by nets for local use.
|Personal Favors
|—
|
|
|
|
|-
|10-80
|
|
|... tower lights at this station burned out.
| rowspan="2" |—
| rowspan="2" |—
|
|
|Chase
|
|-
|10-81
|
|
|Officer Nr. ... will be at your station ...
|
|
| rowspan="8" |—
|
|-
|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.
| rowspan="5" |—
|—
|
|
|
|-
|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
|
|-
| colspan="9" |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) ...
| rowspan="2" |—
|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
|
|
| rowspan="2" |—
|
|-
|10-94
|
|
|Test—no modulation—for frequency check.
|Give me a test
|Drag racing
|
|
|
|-
|10-95
|
|
|Test intermittently with normal modulation for ...
| rowspan="5" |—
|—
|
|
|Prisoner in custody
|
|-
|10-96
|
|
|Test continuously with tone modulation for ...
|Mental subject
|
|
|—
|
|-
|10-97
|
|
| rowspan="3" |—
|—
|
|
|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.
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 (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 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.
{| class="wikitable"
|+ICS Clear Text Guide
- 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
- The New York Fire Department uses its own ten-code system.
- Fire and Emergency New Zealand uses a system of "K-codes" to pass fire appliance availability statuses as well as operational messages. For example, "K1" means "proceeding to incident", "K99" means "Structure fire, well involved", and "K41" means "fatality" (a reference to the Ballantyne's fire, New Zealand's deadliest, which killed 41 people). The New Zealand Police also use some K-codes, with completely unrelated meanings to those used by FENZ; 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, and provides codes standardized by meaning in all languages – essential for international shortwave radio communications.
- Z codes are used for military radio communications NATO countries, and like Q codes are standardized across languages.
See also
- Advanced Medical Priority Dispatch System
- Emergency service response codes
- List of CB slang
- List of international common standards
- Medical Priority Dispatch System
- NATO phonetic alphabet
- Radiotelephony procedure
- Procedure word
- Spelling alphabet
References
External links
- Official TxtFire Philippines website
- The APCO Bulletin, January 1940 – The first official publication showing the 10-codes.
- Official Ten-Code List Association of Public Communications Officers (APCO)