CB Radio 10 Codes: Meanings, Channel 9, and FCC Rules

CB radio 10 codes are two-digit numeric shortcuts, each spoken as “ten” followed by a number, that let Citizens Band operators exchange common messages quickly over noisy channels. The list below covers the codes you are most likely to hear or need, how to send them so they actually get through, and the FCC rules that shape what you can say on the air.

The Core Codes You Will Hear Most

These are the everyday signal-and-status codes. If you learn nothing else, learn these.

10-1: Receiving signal is very weak, barely readable.
10-2: Receiving signal is strong and clear.
10-3: Stop transmitting. Used to clear the channel.
10-4: Message received and understood. The most recognized code in the system.
10-5: Relay a message to another station.
10-6: Busy, stand by.
10-7: Going out of service or turning off the radio.
10-8: Back in service, ready to receive.
10-9: Repeat your last transmission.
10-10: Standing by, monitoring the channel.

Location, Channel, and Information Codes

The second tier of codes handles the practical business of finding people, moving between channels, and asking basic questions.

10-12: Visitors or others present at the station.
10-13: Report on road or weather conditions.
10-17: Urgent business or matter.
10-20: What is your location? Second only to 10-4 in recognition, and now common in everyday speech.
10-25: Can you contact a specific person?
10-27: Moving to a different channel.
10-30: Transmission does not conform to FCC rules.
10-36: What is the current time?

Emergency Codes and Channel 9

A handful of codes signal that someone needs the channel cleared or needs help.

10-33: Emergency traffic at this station.
10-34: Need help at this station.
10-35: Confidential information follows.
10-70: Fire at the reported location.
10-71: Proceed with caution.

A 10-33 is the most serious signal you will hear on CB. When one goes out, every other operator on the channel should stop transmitting and keep the frequency clear. Channel 9 (27.065 MHz) is reserved by the FCC for emergency communications and traveler assistance, so a 10-33 there gets absolute priority.¹ The five-minute limit that normally caps a conversation does not apply during emergency traffic or when you are assisting a highway traveler, so an operator in trouble can hold the channel as long as needed.²

Channel 19 (27.185 MHz) is the unofficial trucker channel. Most long-haul drivers monitor 19 for road conditions and traffic. That is a convention rather than an FCC rule, but it is nearly universal on U.S. highways.

Trucker Variations You Will Also Hear

Beyond the standardized set, trucking culture has added informal codes for everyday road life. They are not in any FCC regulation, but they are widely understood.

10-100: Stopping for a restroom break.
10-200: Police activity reported in the area.

A 10-200 exists because drivers wanted a compact way to share information about police presence. Sharing truthful observations about road conditions is not by itself a violation. Operators run into trouble when coded language crosses into coordinating illegal activity or deliberately interfering with law enforcement communications, both of which the FCC prohibits.³

How to Send a Code So It Actually Gets Through

The mechanics of speaking into a CB matter more than newcomers expect. Press the push-to-talk button and pause for a fraction of a second before saying anything. That pause lets the carrier wave reach full strength. Start talking immediately and your first syllable gets clipped, so “10-20” arrives as “-20,” which could be almost anything.

Say “ten,” leave a brief gap, then say the number. “Ten… four” is easier to copy through static than “tenfour” run together. Keep your voice at a normal conversational volume. Shouting overdrives the microphone and distorts the signal, which defeats the purpose of using standardized codes in the first place. Release the push-to-talk button a beat after you finish speaking so your last word does not get cut off.

The Breaker Protocol

To join a conversation already in progress, wait for a pause between transmissions, then say “breaker” followed by the channel number. That signals the current operators that someone else wants in. Jumping in mid-conversation without announcing yourself is poor etiquette and creates confusion on busy channels like 19. If you have an emergency, say “breaker one-nine, 10-33” to claim priority.

What the FCC Rules Actually Say About 10 Codes

You do not need a license to operate a CB radio. The FCC classifies CB as part of its Personal Radio Services, and among those services, only GMRS requires a license.⁴ Anyone in the United States can buy a certified CB radio, install it, and transmit as long as they follow 47 CFR Part 95, Subpart D.

The regulations call for “plain language voice communications,” which creates some ambiguity around 10 codes. The FCC has never specifically banned them on CB, and the rules do not carve out an explicit exception either. In practice, 10-code use is universal on CB channels and enforcement has focused elsewhere.²

What the FCC does actively prohibit: using a CB station in connection with any illegal activity, transmitting false or deceptive communications, broadcasting obscene or profane language, and intentionally interfering with other stations.³ CB-specific rules also bar advertising, communicating with foreign stations other than Canadian General Radio Service stations, transmitting music or sound effects, and rebroadcasting material for radio or television.²

Break the rules and two things can happen. Your authorization to operate is automatically voided.² The FCC can also impose monetary forfeitures of up to $10,000 per violation against individual operators, with a $75,000 ceiling for a continuing violation.⁵ The FCC has proposed fines as high as $25,000 against individual CB operators for unauthorized operation combined with willful interference.⁶ In serious cases, the government can seize the equipment itself.⁷

None of the common 10 codes above put you anywhere near those lines. The rules exist for people jamming channels, running illegal amplifiers, or using CB to coordinate something illegal. Ordinary code traffic among truckers and hobbyists is not what the FCC is looking for.

1
Federal Communications Commission. Citizens Band Radio Service (CBRS)
2
eCFR. 47 CFR Part 95 Subpart D – CB Radio Service
3
eCFR. 47 CFR 95.333 – Prohibited Uses
4
Federal Communications Commission. Personal Radio Services
5
Office of the Law Revision Counsel. 47 USC 503 – Forfeitures
6
Federal Communications Commission. FCC Enforcement Bureau Proposes 25K Fine Against Jayme John Leon
7
Office of the Law Revision Counsel. 47 USC 510 – Forfeiture of Communications Devices