Police 10 Codes: Complete Guide to Radio Ten-Codes & Signals

What are 10-codes?

10-codes (or “ten-codes”) are short radio signals like 10-4 or 10-8 that compress common messages into quick, standardized phrases. They were created to keep radio traffic short and clear on early analog systems.

Why do they vary?

There is no single national 10-code list. States, regions, and even neighboring agencies often use slightly different meanings for the same code (for example, 10-13 or 10-33). Always follow your department’s official list.

Ten-codes vs. plain English

After 9/11, many agencies and federal partners moved toward plain-language radio traffic to avoid confusion during multi-agency incidents. Many departments now use a mix of plain English and a small core of 10-codes.

10-Code	Typical Meaning	Notes / Variations
10-1	Unable to copy / weak signal	Check volume, location, or repeater. Some agencies use 10-1 for “Return to station.”
10-2	Signal good / loud and clear	Radio check response. Can also be paired with unit number during shift start.
10-4	Acknowledgment / OK	Probably the best-known 10-code. Simple “Copy” or “Received.”
10-6	Busy — stand by	Often used when tied up on another call or administrative task.
10-7	Out of service	Unit temporarily not available for calls. May pair with reason code locally.
10-8	In service / available	Unit cleared and ready for new calls. Commonly logged by CAD.
10-9	Repeat last transmission	Used when radio traffic is unclear or covered.
10-10	Fight in progress / negative	In some systems 10-10 is a specific call type; in others it simply means “Negative” or “No.”
10-12	Visitors present / remain discreet	May signal that non-sworn persons are nearby and radio traffic should be filtered.
10-13	Weather / road conditions or officer needs help	Meaning varies widely. In some states 10-13 is strictly a weather check; in others it signals officer in danger. Critical to confirm locally.
10-16	Domestic problem	Domestic disturbance or domestic dispute; may be broken down into additional codes.
10-19	Return to station	Sometimes used for “En route to station” for paperwork or briefing.
10-20	Location	As in “What’s your 10-20?” meaning “What is your exact location?”
10-21	Call by telephone	Often used for sensitive information that should not be broadcast openly.
10-22	Disregard / cancel	Cancel previous message or assignment unless otherwise directed.
10-23	Arrived on scene	Used when the unit reaches the call location; tied to CAD timestamps.
10-27	Driver license information	Running a subject by name, DOB, or license number for status and class.
10-28	Vehicle registration / plate check	Used to query DMV or local databases for vehicle ownership and status.
10-29	Warrant check	Check for wants/warrants on a person or vehicle; may include caution flags.
10-32	Armed subject / person with a gun	Meaning varies; always verify your local definition and officer safety protocols.
10-33	Emergency traffic only	Used to clear the air so only priority traffic goes out, often during critical incidents.
10-36	Correct time	Sometimes used when dispatch gives the official time for reports or logging.
10-41	Beginning tour of duty	Shift on; unit is going in service for the day or night.
10-42	End of tour of duty	Shift off; unit going out of service. Also used ceremonially in line-of-duty deaths.
10-97	On scene	Alternative to 10-23 used in some regions. In others it means “Signal check.”
10-98	Finished with last assignment	Clear from prior call and typically ready to go 10-8 (in service).

Important: This is a generic training reference. Ten-code meanings can change dramatically from one agency or state to another. Always use the official list in your department policy, regional communications plan, or academy curriculum.

Ten-Signals, “Signal” Codes, and Local Variants

In addition to 10-codes, many agencies use ten-signals (like “Signal 13”) or plain signal codes (such as “Signal 7” for a deceased person). These systems evolved locally and can be totally different a few counties away.

Signal codes often map directly to specific call types (e.g., burglary, robbery, overdose).
Priority codes may indicate urgency or response level (Code 1, Code 2, Code 3).
Disposition codes summarize how a call was handled for CAD and reports.

Bottom line: treat this site as a broad reference, then always match your local training bulletins, EMD/EMS cards, and communications SOPs.

Why standardization matters

During mutual aid events, disasters, or task force work, mismatched code lists can create real confusion. That’s one reason NIMS and ICS guidance encourages plain-language radio traffic for multi-agency operations.

Many departments keep a core set of 10-codes for routine administrative traffic but lean on plain English when working with outside partners, federal teams, or statewide incident management groups.

Radio shorthand

10-codes, signal codes, and response codes are designed for speed and clarity over the radio. They don’t usually appear in the statute books and can be changed by policy at the agency or regional level.

When the radio is busy or multiple incidents are unfolding, tight, predictable shorthand helps dispatch triage calls, track units, and keep officer safety traffic from getting buried.

Charge language and case reports

When it comes to reports, charging documents, and court filings, what matters is your state’s criminal code. That’s where exact elements, penalties, and statute numbers live.

To explore those for your area, use our State Police Codes Index and select your state. Each state page connects 10-code concepts with local statute structure, common charge types, and training pointers.

Best Practices for Learning 10-Codes

Start with your official list. Print or save your agency’s communications SOP, field guide, or academy handout. That is the version that matters.
Learn by call type, not just numbers. Group 10-codes by function: status codes (10-7, 10-8), queries (10-27, 10-28, 10-29), emergencies (10-33), etc.
Practice out loud. Run mock dispatch scenarios, practice checking in and clearing calls, and announce your location and status using proper radio etiquette.
Know when to switch to plain English. In critical incidents, mutual aid operations, or when directed by communications, plain language is often the safest option.
Monitor how senior officers talk. Ride-along time is a free masterclass. Note which codes are actually used and which live only on the laminated card.

Common training mistakes to avoid

Assuming internet lists are correct for your region.
Memorizing so many 10-codes that you freeze on the air.
Using slang or internal jokes on recorded channels.
Forgetting to give your location before emergency traffic.
Relying solely on codes when supervisors want clear, plain-English updates.

Use this page as a global reference, then tighten it down to your agency’s exact code sheet and communications expectations.

Are police 10-codes the same in every state?

No. There is no national, mandatory 10-code standard. Many agencies started from early APCO lists but customized them over time. The same code can mean different things in different regions, which is why you must rely on your agency’s official list.

Do officers still use 10-codes, or is it all plain English now?

It depends on the agency. Some departments have moved almost entirely to plain-language radio traffic, especially for major incidents and inter-agency operations. Others still use a full 10-code set. Many sit in the middle: plain English for complex calls, a handful of 10-codes for routine status and queries.

What is the most important 10-code to learn first?

Generally, recruits should master status and safety codes first: 10-4 (acknowledge), 10-8 (in service), 10-7 (out of service), 10-20 (location), 10-23 or 10-97 (on scene), 10-33 (emergency traffic), and any local “officer needs help” code. Your FTO or academy staff can prioritize the exact list.

Can civilians or ride-along guests use 10-codes?

In most places, ride-along guests and civilians are not expected to use 10-codes. If you need to speak on the radio, simple, clear English is usually best. Local policy and the supervising officer will guide you.

Where can I find my agency’s official list?

Check your academy handbook, FTO binder, communications SOP, or CAD field guide. Many agencies also keep a laminated card in patrol units. When in doubt, ask dispatch staff or your supervisor for the latest version.

Next Step: Learn Your State’s Statutes and Local Police Codes

10-codes are only one part of the puzzle. To really understand how officers talk about calls, charges, and reports, connect them to your state’s criminal code and local police codes.

Browse State Police Codes Back to PoliceCodeGuide Home

Police 10-Codes & Ten-Signals