Police Signal Codes vs 10-Codes vs Penal Codes: 2026 Guide

Listen to enough police radio and the numbers start to blur. “Signal 7 on the shoulder.” “10-8, back in service.” “Got a 459 at the warehouse.” All three sound like the same kind of thing, and they aren’t. Police code and signals belong to different systems, each answering a different question, and mixing them up is the fastest way to misread a scanner feed.

Here is the short version. Signal codes label what kind of incident is happening. 10-codes handle radio housekeeping: who is where, who is available, who heard what. Penal codes are real criminal statute numbers that officers speak aloud to name a crime. One tells you the event, one tells you the status of the officer, and one tells you the offence.

This guide sorts the three, shows where they collide, and gives you a way to tell which system you are hearing before you trust a meaning. Our earlier comparison of 10-codes, 11-codes and penal codes covers the California side of the picture. This one is built around signals, which that article only touches, and around the Southeast, where signals do most of the talking.

The Three Systems at a Glance

Notice the middle row. Penal codes are the only one of the three that has an official source. Signals and 10-codes are conventions, which is why the same number can mean two things a county apart.

Signal Codes: Labels for the Incident

A signal code is a numbered label for a type of call. Instead of saying “dead person,” a Florida officer says “Signal 7.” Instead of “stolen car,” the same officer says “Signal 9.” The number does the work of a short description, and the officer saves airtime.

Signals are most closely associated with Florida and Georgia, and they show up in other Southern states too. Florida’s system traces to the Highway Patrol in the 1950s and spread outward to sheriff’s offices and city departments. Georgia agencies run their own signal lists, some with well over a hundred entries. For full tables of each, see our guides to Florida police codes and signals and Georgia police codes.

Three things define a signal:

• It describes the event, not the officer. A signal tells you a crash, a fight or a death is involved. It says nothing about whether the officer is on scene.
• It belongs to an agency. Nobody maintains a national signal list. Each department wrote its own, and they drifted apart.
• It usually sits beside a 10-code. Signals carry the content of a call, and a short set of 10-codes carries the movements around it.

That last point matters most when you are trying to follow a transmission. A Florida deputy might report a “Signal 4 with injuries,” then give a location, then go on scene. The signal is the news. The rest is logistics.

10-Codes: Radio Housekeeping

Ten-codes are the system most people picture first. Charles Hopper of the Illinois State Police developed the format in the late 1930s, and the Association of Public-Safety Communications Officials (APCO) later published standard lists. The “ten” prefix originally gave early transmitters a moment to reach full power before the number that mattered was spoken. For the full history, our US 10-codes guide and the full 10-codes list cover it.

What a 10-code does is manage the conversation:

• 10-4 acknowledges a message.
• 10-8 says the officer is in service.
• 10-7 says the officer is out of service.
• 10-20 asks for or gives a location.
• 10-97 says the officer is on scene.

Ten-codes are the most portable of the three systems because they trace to the same APCO source. They are also the most overrated in terms of consistency. APCO’s list was a recommendation, adoption was voluntary, and agencies edited it freely. A scanner listener who assumes every 10-code means what the textbook says is the one who gets caught out, and the next section shows how.

Penal Codes: The Statute Number on the Air

Penal codes are different in kind. They are not radio shorthand. They are section numbers from a state’s criminal code, spoken aloud so a dispatcher and officers know what offence is being reported.

California is where this habit is strongest. Officers there routinely say the penal code section on the air:

Each of these has its own page here, including 187, 211 and 459, and the broader California penal codes page lists more.

Two cautions keep people honest here. First, “penal code” gets used loosely. 5150 is a Welfare and Institutions Code section about involuntary mental health holds, not a Penal Code section, and 11350 is a Health and Safety Code section about controlled substances. Both get called “police codes” in everyday speech, and both are statutes, so they behave like penal codes on the air. You can read more in our pages on 5150 and 11350.

Second, not every three-digit number is a statute. 925 is a good example: it is a radio code whose meaning depends on the agency, and some agencies use it for a suspicious person while others use it for something else. Our 925 page goes through the variations. A three-digit number on California radio is a strong hint of a penal code, but it is only a hint.

Also remember that a penal code is only meaningful in its own state. California defines burglary at section 459. Another state’s burglary statute carries a different number, so “459” tells you nothing outside California.

Where the Systems Collide

The reason this topic confuses people is that the same digits show up in more than one system, and the same number gets different meanings within a single system. A few examples from the agencies we cover:

The Signal 4 row is the cleanest illustration of the problem. A Florida listener who hears “Signal 4” thinks crash. A Georgia listener who hears the same words may be hearing a dispatcher tell a unit to stand down. Neither is wrong. They are using different dictionaries.

The 10-1 and 10-13 rows are more serious, because those are the codes that may signal an officer in danger. A listener or a new dispatcher who carries the textbook meaning into Chicago or New York would misread the single most urgent message on the channel. This is why every guide on this site ties a meaning to an agency instead of presenting one master list.

There is also a trap in the other direction: the “emergency” signal is not the same number across the South. Florida lists Signal 0 as officer needs help, while the Georgia list we cover uses Signal 99, and Signal 100 in Florida clears the air. If you follow more than one agency, write down that agency’s emergency code first.

How to Tell Which System You Are Hearing

You do not need to memorise every list. You need to sort the number into the right bucket first. A few cues help:

1. Listen for the word. If the officer says “signal,” it is a signal. If the officer says “ten” before the number, it is a 10-code. “Eleven” points to an 11-code, the California traffic set covered in our 11-codes guide.
2. A bare three-digit number in California is probably a penal code. “We have a 211 in progress” is a robbery. The pattern is a number with no prefix, naming a crime.
3. Ask what job the number is doing. If it names an event, think signal. If it reports where an officer is or whether they are available, think 10-code. If it names a crime, think penal code.
4. Check the state. Southern agencies lean on signals. Most of the rest of the country leans on 10-codes or plain language. California layers everything.
5. Check the agency before the meaning. The agency matters more than the number. If you do not know who is talking, you do not know what the number means.

Our guide to reading police scanner codes goes further on matching what you hear to the right system.

How They Stack in a Real Transmission

The three systems often share a single sentence. Two made-up but realistic examples show how.

Florida. A deputy comes on the air: “Signal 4, northbound lanes at mile marker 214, injuries, requesting fire rescue. 10-23.” Then, later: “10-8.” The signal names the event, the 10-codes mark the officer’s arrival and return to service, and everything else is plain language.

California. A dispatcher says: “Unit 5-Adam-12, 211 in progress, Code 3.” The penal code names the crime and the response code sets the urgency. The unit replies “10-4,” a status acknowledgement. In one exchange the call uses a penal code, a response code and a 10-code, which is why California channels sound number-dense. For the response-code layer, see our guides to emergency response codes and what Code 4 means.

Georgia adds another layer on top: status codes that record how a call ended, such as the “10-8, Stat 7” pattern some agencies use. So a fully loaded Georgia transmission can contain a signal, a 10-code and a status code at once.

Why There Is No Single Standard

People often ask why nobody fixed this. Part of the answer is that nobody had the authority. The United States has roughly 18,000 law enforcement agencies, and no federal body orders them to share one code list. Each agency wrote its own procedures, and the lists that worked locally stayed.

The cost showed up in 2005. During the response to Hurricane Katrina, officers from different agencies could not rely on each other’s codes. Federal guidance, including the SAFECOM program and the National Incident Management System, then pushed agencies toward plain language for multi-agency work. Many departments now use codes for routine traffic and plain English when they work with other agencies. Outside the United States the picture is simpler still: the United Kingdom and most other countries never adopted numbered signal systems at all. Our UK police code list shows how a plain-language approach looks in practice.

Encryption adds a second wrinkle. Some agencies, including the Georgia State Patrol for much of its traffic, have moved to systems an ordinary scanner cannot monitor. Before you spend time learning one agency’s signals, check that you can still hear it.

Quick Reference: Which Question Does Each Code Answer?

• “What happened?” Signal code (Florida, Georgia, parts of the South).
• “What is the officer doing or saying?” 10-code (acknowledge, location, in service, on scene).
• “What crime is it?” Penal code or other statute number (California most of all).
• “How fast are they going?” Response code (Code 1 through Code 4).
• “What happened on the roadway?” 11-code (California Highway Patrol and neighbours).
• “How did the call end?” Status code (some Georgia agencies).

If you can answer which question a number is answering, you can usually find the right list to check it against.

Tips for Getting It Right

• Say the agency out loud before you say the meaning. “Florida Highway Patrol Signal 20” and “Broward Signal 20” are different sentences.
• Do not borrow a meaning across state lines. A signal or penal code number that is routine in one state may mean something else, or nothing, in the next.
• Treat any list as a baseline. Agencies revise their codes. For anything that matters, confirm with the agency’s current published list.
• Learn the emergency code first. For every agency you follow, know the officer-needs-help code before anything else.
• Keep statutes and radio codes apart. 187 is a law. 10-8 is a convention. They sit in different places on the page and in your head.

Using Police Code to Explore Further

Police Code is a free, ad-free police code explorer built for the moment when a number does not match the list in your head. You can look up a signal, a 10-code or a penal code, compare how it changes between agencies and countries, and move from there to the full police code lists, the US police code overview or the complete list of police codes. For the smaller radio families that do not fit the big three, the other police scanner codes page is a useful stop.

Police code and signals only look like one system from a distance. Up close they are three tools: signals name the event, 10-codes manage the radio, and penal codes cite the law. Sort each number into its bucket, tie it to an agency, and a scanner feed that sounds like noise starts to read like a report.