Ten-code

Ten-codes, properly known as ten signals, are code words used to represent common phrases in voice communication, particularly by law enforcement and in Citizen's Band (CB) radio transmissions. The codes, developed in 1937 and expanded in 1974 by the Association of Public Safety Communication Officials (APCO), allow for brevity and standardization of message traffic. They have historically been widely used by law enforcement officers in North America, although some departments have controversially attempted to prohibit their use.

While ten-codes were intended to be a terse, concise, and standardized system, the proliferation of different meanings may render them useless in situations where people from different agencies and jurisdictions need to communicate. For that reason their use is expressly forbidden in the Incident Command System. Some organizations and municipalities also use other codes in addition to the ten-codes. An example is the California Highway Patrol's use of eleven-codes, and the use by the Port Authority Police of eight codes as part of their communication.

Historic overview

Ten-codes were developed in the 1940s at a time when police radio channels were limited, to reduce use of speech on the radio. Credit to the originator goes to Charles "Charlie" Hopper. He was the Communications Director at the Illinois State Police, District 10, located in Urbana, Illinois. Hopper was involved in radio for many years and saw a need to abbreviate radio transmissions on State Police bands. Experienced radio operators know that the first syllable of a transmission is frequently not going to be understood, but is a necessary part of "tuning in"; hence preceding every code with "ten" allows a better chance of understanding the critical portion. Ten-codes were later adapted for use by CB radio enthusiasts before its pop culture explosion in the late 1970s. The tremendous popularity of the 1975 Convoy song by C.W. McCall depicting droll conversation among CB-communicating truckers put several phrases, such as 10-4 for "understood" and what's your twenty? (10-20) for "where are you?" into common and enduring use in American English. The song was followed by a 1978 movie Convoy which further entrenched the use of ten-codes in casual conversation.

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 high variability in meaning (see the November 2005 articles in External links, below). The Department of Homeland Security reportedly has plans to do away with 10-codes as well, in favor of "Plain English" while the nationally-standardized Incident Command System specifically prohibits ten-codes. As of 2025, ten-codes remain in common use.

List of ten-codes

The following list, given in ascending order and grouped by decade, illustrates the current usage of various ten-codes. Only a handful of them are standardized. Some are fairly consistent, while others (such as 10-40) can have completely different meanings, many of which are not listed here.

Presentation:

• Multiple meanings for the same code are in a bulleted list
• The first bold definition is the current APCO specification.
• Popular alternate meanings follow in bold.
• Less common meanings are in regular typeface
• Meanings specific to CB radio are set in italics.

10-0s

Code	Meaning(s)
10-00	Officer Down, All Patrols Respond '(Ten-Double Zero)'
10-0	Caution Death/Dead Pursuit Unit logging off (NZ Police)
10-1	Poor Reception Officer Needs Help Unable to Copy Call your command (New York City) Message to all units (NZ Police)
10-2	Good Reception OK For Now, Continue With Status Checks Return to your command (New York City) Unit is en Route to job (NZ Police)
10-3	Stop Transmitting Ok, No Further Status Checks Needed Call your dispatcher {aka 'Central'} (New York City) Unit available (NZ Police)
10-4	Message Received Affirmative Ok Understood Repeat your last transmission (NZ Police)
10-5	Relay Pick up an item Repeat message (New York City)
10-6	Busy Out At Call Stand by (New York City)
10-7	Out of Service Ending tour of Duty Deceased Not functional (as a vehicle) (Ambulance) On Scene Request Break Proceeding to ___ Unit has arrived at job (NZ Police)
10-8	Back In Service On Duty Available for next Call (Ambulance) In Service / En Route
10-9	Repeat last message

10-10s

Code	Meaning(s)
10-10	Fight In Progress Out of service, off duty Permission to go on common channel (car to car transmission, rather than through dispatch) Negative Transmission completed Welfare check Other non-Criminal Event On Break, Subject To Calls Possible Crime {Shots fired, suspicious person etc.} (New York City) Person with felony warrant (Michigan) Officer requires immediate assistance (NZ Police)
10-11	Animal Problem Road-side check Talking too fast Alarm call Person who reported the alarm ("Who's the 10-11 on this?") En route Alarm, specify type (New York City)
10-12	Standby Visitors present Disregard Call in reports At scene Check revocation Security Holding, usually inside a store (New York City)
10-13	Advise Weather/Road Conditions Officer in need of assistance Mental health patient transport Officer needs immediate assistance (New York City) Running late by ___ minutes (Public Transportation)
10-14	Suspicious Person/Report of Prowler Convoy or escort Check Plate, Vehicle is occupied and suspicious, check if stolen (New York City) Back on time (Public Transportation)
10-15	Civil Disturbance Prisoner/suspect in custody Check if Vehicle Stolen - People in or out rolling/stationary vehicle. Domestic disturbance Check Plate, whether occupied or otherwise, check if stolen (New York City)
10-16	Domestic Disturbance Make pickup at ___ Non-urgent business (lights and siren not necessary) Vehicle Stolen Prisoner License Check reports stolen (New York City)
10-17	Meet Complainant Pick up papers at ___ Urgent business (lights and siren) Conduct Investigation Vehicle Not Stolen En Route Medical Emergency Writing Report License Check reports not stolen (New York City)
10-18	Urgent Complete assignment ASAP Anything for us? Intoxicated (as a noun or an adjective) Livestock on Roadway Warrant Check shows active warrants (New York City)
10-19	Return to ______ Returning from Scene Return/En Route To Station Warrant Check shows no active warrants (New York City)

10-20s

Code	Meaning(s)
10-20	Specify Location/My Location is ___/Location Report of past robbery (New York City)
10-21	Please Call ___ Phone Call Report of past burglary (New York City)
10-22	Disregard Report to ___ Send blood technician Report of past larceny, specify type (New York City)
10-23	Arrived at Location/On Scene Stand by on this frequency Status check En route to call Sex offense Meet with officer
10-24	EMERGENCY BACK UP Clear call/stop Trouble at station Unit not available Direct traffic Report of past assault (New York City)
10-25	Report to ___ Please Contact ___ Officer Needs Help Report of past child abuse (New York City)
10-26	Detaining Suspect (implying "Please expedite") Check auto registration ETA ___ Disregard last info Phone residence Call canceled Message Received
10-27	Request Drivers License Check Vehicle Registration Request I am moving to channel ___ Motor Vehicle Accident Traffic stop Felony crimes as follows (the "10" portion being commonly unstated): 27-1 Homicide 27-2 Rape or sexual assault 27-3 Armed robbery 27-4 Aggravated battery 27-5 Burglary (commercial or residential) 27-6 Theft 27-7 Auto theft 27-8 Shooting 27-9 Stabbing
10-28	Request Vehicle Registration Check Driver's license request Identify your station Missing person
10-29	Request Arrests/Warrants Check Time is up for contact Stolen Vehicle Other past crime, specify (New York City)

10-30s

Code	Meaning(s)
10-30	Unauthorized use of radio Danger/caution Special check at ___ Juvenile Robbery in progress (New York City)
10-31	Crime in progress In pursuit Domestic disturbance Check for local warrants Suspicious person or situation Burglary in progress (New York City)
10-32	Person with gun Fight in progress Radio check (not frequently used, see 10-33 below) Check NCIC DWI test Medic down Breathalyzer Larceny in progress, specify type (New York City)
10-33	Emergency, all units stand by Officer needs help / the life of the officer is in danger Disturbance at ___ Emergency Traffic Fire Threat or confirmed sighting of a bomb/explosive device (New York City) Radio check (This is the most common radio check request used by CBers, as denoted in the classic line from C. W. McCall's song "'Round the World with the Rubber Duck" in 1976: "Break one-nine for a 10-33, what we got was the cotton-pickin' BBC.")
10-34	Riot Frequency open (cancels 10-33) Help needed Trouble at jail Correct time Meet officer Assault in progress (New York City)
10-35	Major crime alert Confidential information Suspicious person Record check returns Misdemeanor/Felony warrant Child abuse in progress (New York City)
10-36	Correct time of day? Confidential information
10-37	Suspicious vehicle Identify yourself Wrecker needed at ___ Shoplifter Time of day? Operator on Duty
10-38	Stopping suspicious vehicle Traffic Stop Ambulance needed Station report satisfactory Road Block Phone communications Vandalism
10-39	Investigate suspicious vehicle Run with lights & siren Your message was delivered Backing Up____ False alarm, premises were occupied Contact officer Disturbance Resume previous assignment Revert to prior status Motorist Assist

10-40s

Code	Meaning(s)
10-40	Run silent (no lights & siren) False alarm, no activity, premises appears secure Please tune to channel ___ Expedite Advise if available Suspicious person Dead animal Mental patient Fight Meal Break Shots fired Out at station/office Don't divulge location
10-41	Begin duty Radio test Intoxicated person Debris in street Switch to alternate channel Neighbor trouble Officer is out on a meal break Female in Police Unit (Specifically someone of the opposite sex)
10-42	End duty "Flush and Clean" Traffic accident at ___ Malicious mischief Request dispatch times Home Fatality Call home
10-43	Information Traffic jam at ___ Request criminal history Pick up passenger Armed robbery Rescue call Request officer
10-44	Permission to leave patrol I have a message for you Transmission received Possible mental subject Traffic accident (no injury) Stolen (mostly vehicles) Fatality Suicide or attempt Driver's license clear Haz-Mat condition (New York City)
10-45	Animal carcass Pick up officer Fatality Drivers License/Warrant Check Fire alarm Fueling vehicle All units in range please report Traffic accident (injury) Property damage/car accident (non-injury)
10-46	Motorist assist Motor vehicle accident (MVA) Wrecker Car accident (injury)
10-47	Emergency road repair Disorders and family trouble Missing person Drunk driver Blood run Paper Work Request ambulance
10-48	Traffic control Request criminal history Did you copy? Runaway juvenile Use caution Request wrecker Ready to copy information Blood alcohol report
10-49	Traffic light out EMERGENCY, clear air En route to assignment Any traffic/pending calls for this unit? Warrant Pedestrian on freeway Serving warrant Intoxicated/reckless driver

10-50s

Code	Meaning(s)
10-50	Officer Welfare Check Traffic Stop Accident Often referred to as a 10-50 PD (Property Damage), a 10-50 PI (Personal Injury), or (rarely) 10-50 F (Fire or Fatality) No/negative Break channel Auto accident with property damage Disorderly person/group (New York City)
10-51	Wrecker needed Auto accident with injuries Phone message En route Wandering gang, specify # of persons and direction
10-52	Ambulance needed Accident with Injuries Fatal auto accident Message for assignment Estimated Time of Arrival Audible alarm Dispute, specify if weapons, injuries (New York City)
10-53	Road blocked Silent alarm En route to office Intoxicated/disorderly person Officer is clear (from traffic stop/call for service) Vehicle accident, specify if property involved or if injuries (New York City)
10-54	Negative Animals on highway Fatal Accident Silent pursuit Traffic stop, dangerous vehicle/location Aided case {Injury, illness}
10-55	Intoxicated driver or DWI Security check Ambulance call Coroner requested
10-56	Intoxicated pedestrian Intoxicated Driver Warrant indicated Arrived at scene Change location
10-57	Hit & run accident Intoxicated Person Narcotics Officer at pistol range
10-58	Direct traffic Wrecker DOA Teleprinter message Mental patient (violent)
10-59	Escort or convoy Out of car checking violation Ambulance Bomb threat Mental patient (non-violent)

10-60s

Code	Meaning(s)
10-60	Squad in vicinity Traffic stop Subject negative What is next message number? Assist motorist Major emergency Canceled Coffee break
10-61	Personnel in vicinity (Is the subject within earshot of your radio?) Subject has record - not wanted Stand by for CW traffic Clear of traffic stop Weather conditions? Lunch break
10-62	Reply to message Subject possibly wanted Unable to copy, use phone Check for rising water Logged on/off Unit involved in a fleet Unauthorized Listener (RCMP)
10-63	Prepare to copy Subject positive Make written copy Net directed to ___ Need barricades Dispatch Coroner/OMI Send Tow Truck (RCMP)
10-64	Local message Subject wanted Message for delivery Net clear, resume normal traffic Field investigator Stopping motorist for moving violation House/Business check Send Ambulance (RCMP)
10-65	Prepare to Copy Net message assignment Assist officer re: 10-64 Kidnapping
10-66	Check Officer's well-being (make sure everything is still ok) Net message cancellation Acknowledge page Subject in observation category
10-67	Clear for next message Subject is parolee Prepare to copy Person calling for help All units comply
10-68	Dispatch message Subject in charged category Repeat dispatch Switch channels
10-69	Message received Clear to copy transmission? Dangerous subject Any calls holding for me? Sniper

10-70s

Code	Meaning(s)
10-70	Fire alarm Fire Wrecker Fire follow-up Prowler Net message Chemical spill In progress (fight, domestic, etc)
10-71	Advise nature of fire Lewd or Sexual Act Ambulance)
10-72	Report progress on fire Subject is in PROHIBITED category (ie-drive, possess firearms, etc)* D.O.A. Prisoner in custody Suicide or Attempted Suicide Fire Truck Turkey Sandwich (New Jersey)
10-73	Smoke report Mental patient Abandoned vehicle
10-74	Negative Theft
10-75	In contact with... Juvenile Trouble
10-76	En route to location See complainant
10-77	ETA Situation Under Control Hijacking
10-78	Need assistance Major accident with injury Request wrecker
10-79	Notify coroner Bomb threat Hit & run

10-80s

Code	Meaning(s)
10-80	Pursuit in progress Subject has been arrested Bomb has exploded Tower lights out On assignment Demonstration Armed & Dangerous
10-81	Traffic stop initiated Breathalyzer request Burglar Alarm Stop for interrogation Officer ___ will be at your station At vehicle maintenance Civil disturbance/riot
10-82	Reserve lodging Stop for interrogation/arrest Traffic signal out Cover assistance Advise location and status
10-83	Work/school crossing detail Call station Units stop transmitting At radio shop Officer in trouble
10-84	Advise ETA Checking officer status My telephone number is ___ Follow-up Broken utility main Special detail Back-up officer
10-85	Arrival delay due to ___ Prepare to copy info My address is ___ Patrol check of___ Loose livestock
10-86	Officer on-duty Utility line down
10-87	Pickup or prisoner transfer Pickup payroll check Dead body Meet with Officer Respond with caution (Glen Cove, NY)
10-88	Advise telephone Station call Special assignment True alarm Officer needs assistance
10-89	Yes Bomb threat Send radio repair Officer at academy Welfare Check

10-90s

Code	Meaning(s)
10-90	Alarm Going Off Bank Alarm Radio repair to be at station Officer at headquarters False alarm Officer in chief's office Missing person Lunch break
10-91	Pick up prisoner/suspect Talk closer to the mike Prepare your inspection Vehicle fuel Bank holdup alarm
10-92	Subject in custody* Parking violation Your signal is weak Officer at court
10-93	Blockage Please check my frequency
10-94	Street racing Change to channel
10-95	Officer's Residence Prisoner/suspect in custody Transmit dead carrier for 5 seconds
10-96	Mental patient Detain prisoner/suspect Request case number
10-97	Record Information J1 Arrest Record Verified By Fingerprints J2 Could Be Armed/Dangerous J3 Has Assaulted Officers Arrived at scene Test signal Possible wanted person in vehicle Welfare check Known offender Officer at court Dead body/Fatality
10-98	Assignment complete Prison/jail break Criminal history indicated Officer at juvenile court Alarm (Glen Cove, NY)
10-99	Cardiac arrest/death Warrants/stolen indicated- J1 Misdemeanor J2 Felony J3 May Be Armed J4 Use Extreme Caution Officer needs assistance/held hostage Message Received(1-Person Unit) Mission complete Unable to receive your signal Traffic stop / violator Need To Use The Restroom (urinate)

10-100s and up

Code	Meaning(s)
10-100	Misdemeanor Warrant Dead body Hot pursuit Riot Conditions Exist Controlled substance Starting Security Check Supervisor (polite)Restroom break.
10-101	Ending Security Check
10-105	Dead on Arrival (DOA)
10-108	Officer down Officer in danger
10-109	Suicide
10-110	Juvenile Disturbance
10-200	Police needed Narcotics, drugs involved
10-1000	Felony Warrant
10-2000	Police required immediately

Other Police Codes

Some other police codes are as follows:

5638

• marijuana

2301

• Public Intoxication

148/149

• DUI/DWI

9560

• Mentally Ill

5150

• Involuntary Psychiatric Hold

1192

• DWI

Parodies

During the 1970s, some truck drivers and CB radio hobbyists responded to the increased use of ten-codes by the general public by inventing parodies of the ten-code with strictly humorous meanings. The best known were the 13-code and the 18-code..

See also

• 10-8: Officers on Duty, a short-lived ABC police drama
• CB slang
• Eleven-code
• NYPD ten-codes
• Q code
• Voice procedure
• Z code

External links

• Los Angeles Sheriff's Department DCS Ten Codes List
• The End of the Ten-Code? – By Tim Dees, Officer.com, 9 November 2005
• 10-4 no more? — By Megan Scott, asap (AP), 25 November 2005
• APCO Bulletin — The APCO Bulletin, January 1940. The first official publication showing the 10-codes (on page 8).
• Official Ten-Code List
• Ten-Codes in Russian