Police Codes: The Complete List (10-Codes, Signals, Penal & Response Codes)

Type “police codes” into a search bar and you’ll get a dozen different lists that all claim to be definitive, and most of them contradict each other. That’s not because anyone’s lying — it’s because there’s no such thing as a single, universal set of police codes. What exists instead is a sprawling, overlapping family of systems: ten-codes, eleven-codes, signals, response codes, and penal codes, each built by different agencies, in different decades, for different reasons, with no central authority ever forcing them into agreement. This guide is the complete map of that landscape — every major family of code, how each one works, where the differences come from, and how to actually read a real transmission once you know what you’re listening to.

The One Rule That Explains Everything

Before any list of codes, one fact has to sit at the front of your mind: there are roughly 18,000 separate law enforcement agencies in the United States, and each one has a meaningful degree of independence over how it communicates. No federal law mandates a single code book. The Association of Public-Safety Communications Officials (APCO) published a recommended ten-code list decades ago, but adoption was always voluntary, and departments modified it freely to suit their own needs.

The result is exactly what you’d expect from 18,000 independent decision-makers: a patchwork. Some codes are nearly universal. Many are not. A handful mean the opposite of their standard definition depending on which department is speaking. Treat every list on this page — including this one — as the widely accepted version rather than an unbreakable law, and always anchor a code’s meaning to the specific agency using it.

Family One: Ten-Codes, the National Baseline

Ten-codes are what most people picture first: “10-4,” “10-20,” “10-50.” Each pairs the word “ten” with a number, and together they form the closest thing American policing has to a common radio language.

Where they came from. The system was developed between 1937 and 1940 by Charles Hopper, a communications director for the Illinois State Police, working with the newly forming APCO. The “ten” prefix wasn’t decoration — it solved a real technical problem. Radios of that era ran on vacuum tubes powered by a dynamotor that needed a fraction of a second to spin up to full transmitting power, and the first syllable of any transmission was routinely clipped before the equipment caught up. Prefixing every code with “ten” gave the radio a throwaway syllable to burn while it engaged, so the number that actually mattered came through clean. That the convention outlived the technology by nearly ninety years is one of the small ironies of American police radio.

How they spread. Once established, ten-codes spread from Illinois across the country, formalised further by APCO’s 1974 Project 14 brevity code. Television did the rest — the 1950s series Highway Patrol put “10-4” into the national ear, and then 1970s citizens-band radio culture, driven by truckers, pushed it into everyday speech, where it survives as a slightly playful way of saying “understood.”

A representative core. No two agencies agree on every entry, but this is the widely used baseline:

10-4 is the exception that proves the rule. It’s one of the only codes that means the same thing almost everywhere — “acknowledged.” That consistency is precisely why it became the one code that escaped into mainstream culture; a code that meant something different in every city could never have become a universal catchphrase the way 10-4 did.

For the full deep dive into where ten-codes came from and why “10-4” specifically stuck, see our guides on why police say 10-4 and the complete 10-1 through 10-99 reference, along with a curated list of the 50 codes you’ll actually hear.

Family Two: Eleven-Codes, California’s Traffic Specialists

Less famous than ten-codes but just as real, eleven-codes are a parallel numbering system built specifically around traffic and roadway incidents. They’re associated above all with the California Highway Patrol, and California agencies often run ten-codes and eleven-codes side by side on the same channel.

The defining feature is granularity around collisions:

11-99 is the CHP’s emergency call — its equivalent of the officer-in-distress signal that other agencies express with an entirely different number, which we’ll return to below. If you’re trying to understand how ten-codes, eleven-codes, and California’s other numbering systems relate to each other, our 10-codes vs 11-codes vs penal codes comparison untangles the whole stack.

Family Three: Signals, the Southeast’s Alternative Dialect

Not every region built its shorthand around “ten-plus-a-number.” A significant swath of the country, especially in the Southeast, communicates through signals instead — “Signal 4,” “Signal 7,” “Signal 20.”

Florida is the clearest example. Its Highway Patrol adopted a signal system back in the 1950s, deliberately distinct from the spreading ten-code convention, and the habit propagated to county sheriffs and city departments across the state. Today Florida runs primarily on signals, with a smaller supporting cast of ten-codes for status and communication.

That Signal 20 entry is worth pausing on, because it’s the single clearest illustration of why anchoring a code to its agency matters. On the Florida Highway Patrol, it means the situation is handled. In Broward County, it means a mentally ill subject. Same two digits, completely different implications for how seriously to treat the call.

Georgia takes signals a step further, layering them with ten-codes and a separate tier of status codes, so a single transmission might carry all three — a signal for the incident, a ten-code for the officer’s status, and a status code for how the call resolved. See our full breakdowns of Florida’s signals and codes and Georgia’s three-layer system for the complete picture.

Family Four: Response Codes, the Urgency Layer

A separate family answers a different question entirely: not “what happened” but “how fast should I get there.” These are the single-digit Code numbers most associated with California policing, and they ride alongside whichever incident-naming system a department uses.

Code 3 and Code 4 form the rhythm of nearly every serious call: units run in hot under Code 3, handle the situation, and someone calls Code 4 to release everyone else. Learning to hear that arc — from emergency to all-clear — lets you follow the shape of an incident even when you miss everything in between. Code 4 trips people up constantly because it sounds urgent but means the opposite: no help needed, situation controlled. And Code 7, the meal-break code, is the most down-to-earth entry in the entire system — a quiet reminder that police radio spends as much time on lunch logistics as it does on emergencies. Full detail on each is in our dedicated guides to Code 4, Code 7 and the other meal-break codes, and Code 3.

Family Five: Penal Codes, When the Law Itself Becomes the Shorthand

This is the family that produces the most famous numbers in American police culture, and it works completely differently from everything above. Penal codes aren’t invented radio shorthand at all — they’re actual criminal statute numbers, spoken aloud because California officers developed the habit of naming a crime by citing the law that defines it.

187 is the one everyone knows, thanks to decades of West Coast hip-hop and film carrying it far beyond any scanner. It’s worth understanding both sides of that fame: as an official code it’s strictly Californian, since other states number their murder statutes completely differently, while as slang it’s near-universal. We cover that split in detail in 187 police code and what does 187 mean.

The rest of the family rewards learning in pairs, because the confusions cluster naturally: 240 and 242 are assault and battery, and the entire distinction comes down to whether contact was made — a swing versus a hit — covered in 240 police code and 242 police code. 211 and 459 are robbery and burglary, constantly confused in casual speech despite naming very different crimes — a taking from a person by force versus an unlawful entry with criminal intent — detailed in 211 police code and 459 police code. 245 escalates assault into deadly-weapon territory, and 415 covers the broad, everyday category of public disturbances, from noise complaints to brewing fights, in 245 police code and 415 police code. And 207, kidnapping, hinges on a single legal element — whether the victim was moved a substantial distance — explored in 207 police code.

Not every California number spoken on the radio comes from the Penal Code, either. 5150 is a genuine involuntary psychiatric hold, but it’s drawn from the Welfare and Institutions Code, not the Penal Code — a civil health process, not a crime, even though it’s spoken exactly like the numbers around it. 11350 is a drug-possession code from the Health and Safety Code, and its real-world severity has shifted twice in a decade through ballot propositions, which makes it one of the few codes on this page whose meaning is still actively changing. 925, by contrast, isn’t a statute at all — it’s a locally assigned radio code for a suspicious person, and unlike the true penal codes, its meaning genuinely varies by department. See what is a 5150 hold, 11350 police code, and 925 police code for how each of these differs from the true statute-based numbers around it.

Family Six: The Phonetic Alphabet, the One Constant

Every family above is regional, contested, and prone to disagreement — except this one. The NATO/ICAO phonetic alphabet (Alfa, Bravo, Charlie, Delta…) is the single genuinely standardised piece of police radio, adopted internationally after testing by the International Civil Aviation Organization in the 1950s and shared today by police, aviation, the military, and maritime radio alike.

Two entries look like typos but aren’t: it’s Alfa, not “Alpha,” so non-English speakers reach for an F sound rather than a P; and Juliett, not “Juliet,” so French speakers pronounce the final consonant instead of silencing it. Some departments — the LAPD most famously — still layer an older name-based alphabet (Adam, Boy, Charles, David) into their unit call signs, so a single transmission can genuinely contain both alphabets at once. The complete printable phonetic alphabet chart covers the pronunciations, the number callouts, and this exact overlap in full.

How the Families Stack: A Real California Transmission

Nowhere do these families collide more than California, where a single serious call can carry four of them at once. Picture a dispatcher sending: “Code 3, 211 in progress, silent alarm, 11-85 requested.” Unpacked: Code 3 is the response urgency (lights and siren), 211 is the penal code naming the crime (robbery), and 11-85 is the eleven-code detail (a tow truck, in this case for a different part of the same broader incident). A ten-code for status, a penal code for the crime, an eleven-code for the roadway detail, and a response code for urgency — four separate systems, four separate historical origins, one transmission.

That stacking is a California specialty. A department that relies purely on ten-codes, or purely on signals, won’t produce transmissions this dense — which is exactly why “learn the ten-codes” is nowhere near enough preparation for following a California scanner, and why the reverse is true for Florida or Georgia.

Why the Same Code Means Opposite Things in Different Cities

If there’s one thing worth internalising from this entire page, it’s that the codes carrying the highest stakes are often the least standardised ones. A few examples make the point sharply:

10-1, in the standard reference list, means a weak signal — mundane radio housekeeping. In Chicago, 10-1 is the officer-in-distress emergency call, the single most urgent transmission the department makes. Same two digits, opposite ends of the urgency scale. Our Chicago police codes guide covers how CPD stripped its code list down to almost nothing and still made this one exception load-bearing.

10-13, in the APCO standard, requests weather and road conditions. In the NYPD, 10-13 means “assist police officer” — an emergency that pulls units from across the surrounding precincts. It’s arguably the single most consequential three digits in American police radio, and it means something almost trivial in the reference book most people would check first. We cover this collision in depth in NYPD 10-13 meaning and the department’s broader, distinctive full NYPD code list, including its signature trick of pairing every major crime with a “past” and an “in progress” version exactly ten numbers apart.

10-50, in Texas, means a traffic accident, often with a severity suffix — 10-50F for fatal, 10-50I for injury, 10-50PD for property damage. In parts of Louisiana, 10-50 means officer down. That gap is not trivia; it’s a genuine hazard during hurricanes, manhunts, and any pursuit that crosses a state line. Our Texas 10-codes guide and LAPD’s three-layer code system both dig further into how regional variation plays out in practice.

10-42 carries a rare dual life: an ordinary end-of-shift code by day, and the number used in the solemn “final call” tradition that marks a fallen officer’s end of watch. Its plain and ceremonial meanings are covered together in what does 10-42 mean. And 10-32, “person with a gun” in most jurisdictions, is a genuine safety-critical code precisely because it isn’t universally standardised — detailed in what does police code 10-32 mean.

The Push Toward Plain Language

If codes are this inconsistent, why do agencies keep using them at all? Mostly because, within a single department, they’re genuinely efficient — fast, unambiguous to the people who use them daily, and lighter on airtime than full sentences. The problem only surfaces when agencies that don’t share a code book have to work together.

That problem became impossible to ignore after Hurricane Katrina in 2005, when responders from different jurisdictions along the Gulf Coast discovered they couldn’t reliably understand each other’s radio traffic during exactly the moment coordination mattered most. In the aftermath, the Department of Homeland Security’s SAFECOM programme and the nationally standardised Incident Command System began actively discouraging ten-codes for multi-agency operations, pushing plain language instead for anything that crosses jurisdictional lines.

The result today is a hybrid that varies agency by agency. Large departments coordinating with outside agencies lean increasingly on plain English for complex incidents while keeping codes for routine internal chatter. Smaller, rural departments that rarely operate outside their own county have often kept their full code lists intact, because the efficiency argument still holds when everyone on the channel shares the same book. Neither approach is wrong; they’re reasonable answers to different operating realities.

Beyond the United States

Because American ten-codes are so culturally dominant — thanks to television and CB radio — it’s easy to assume every country’s police force uses something similar. Most don’t. Plenty of countries police effectively using plain language alone, sometimes paired with a formal legal code structure but with no equivalent of “10-4” at all.

The United Kingdom is a clean example: British policing never adopted American-style numeric radio codes, and officers communicate primarily in plain language, layered with its own legal terminology and structures rather than borrowed numbers. Elsewhere, the picture is even more varied — many countries have no public, standardised radio-code system whatsoever, and generic “code” lists circulating online for those countries are often unofficial or simply borrowed from American sources without basis. If you’re researching how a specific country’s police force communicates, it’s worth checking a dedicated country guide — such as our profiles of policing and emergency numbers across the United Kingdom, Mexico, and Brazil — rather than assuming the American ten-code model as a default. The phonetic alphabet is one of the only things that genuinely does travel unchanged across these borders, since it was built by an international body specifically for that purpose.

How to Actually Use This List

Given everything above, a sensible approach isn’t to memorise all of it at once — it’s to build a small, reliable core and treat the rest as reference material.

Start with the handful of codes that carry the most weight in nearly any system: an acknowledgment code, a location code, an in-service/out-of-service pair, an arrival code, and the response-urgency scale from routine to emergency. That short list, covered in our 50 most common police codes, gets you through the overwhelming majority of ordinary radio traffic. Layer in the phonetic alphabet next, since it’s the one piece of the system that won’t betray you by changing meaning between agencies.

From there, treat everything else as lookup material rather than memorisation. Before trusting any code’s meaning, identify the agency broadcasting it — a city police department, a county sheriff, a state patrol, and a federal agency sharing the same general geography may all use different books. And keep the biggest structural lesson in mind whenever a number surprises you: sort it into its family first. Is it a ten-code (status and communication), an eleven-code (California traffic specifics), a signal (a Southeastern incident description), a response Code (urgency), or a penal code (an actual statute)? Once you know which family you’re listening to, the specific number becomes far easier to place, even before you’ve looked it up.

Using Police Code to Explore Further

Police Code is a global police code explorer built around exactly the problem this page describes: there is no single master list, so the only reliable way to know what a code means is to check it against the agency and jurisdiction actually using it. Instead of trusting one generic chart, you can search an organised database that separates these families, compares usage across departments, states, and countries, and shows the reference behind each entry rather than a guess. It’s free to browse and built for scanner hobbyists, journalists, writers chasing authenticity, dispatch trainees, and anyone who’s ever heard a number crackle across a radio and wanted to know, specifically and reliably, what it actually meant.