10-4 Meaning & CB 10 CODES

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You might have heard someone say “10-4” and wondered what in the world they were talking about. If you’re from a generation that didn’t grow up with CB radios, you might not know that 10-4 is radio code used to indicate that the message has been received loud and clear. But where did this phrase come from, and what exactly does it mean? Let’s find out.

10-4 Meaning


The origins of the phrase “10-4” are a bit murky, but it’s believed to have originated in the early days of CB radio. In those days, before cell phones and the internet, CB radios were one of the only ways for truckers to stay in touch with each other while on the road. Back then, truckers used CB radios to communicate important information about traffic conditions, police activity, and anything else that might be relevant to their fellow drivers.

Since the quality of CB radios wasn’t always great, it was important for truckers to use code words and phrases that would be easy to understand, even if the signal was weak. “10-4” fit that bill perfectly—it was short, sweet, and to the point. Over time, “10-4” became so ingrained in the trucker culture that it spread beyond CB radios and into popular culture at large.

10-4 Meaning



10-1: Receiving poorly.

10-2: Receiving well.

10-3: Stop transmitting.

10-4: Affirmative/I agree.

10-5: Relay message.

10-6: Busy/Hold on a second.

10-7: Out of Service.

10-8 In-Service.

10-9: Repeat message.

10-10: Transmission Completed.

10-11: Talking too rapidly.

10-12: Visitors present.

10-13: Weather/road conditions.

10-14: Not assigned.

10-15: Not assigned.

10-16: Make pickup.

10-17: Urgent Business.

10-18: Anything for us?

10-19: Nothing for you (No).

10-20: Another word for location.

10-21: Call by telephone.

10-22: Report in person to…

10-23: Stand-by.

10-24: Completed last assignment.

10-25: Can you contact me?

10-26: Disregard the last statement.

10-27: I am moving to channel…

10-28: Identify your station.

10-29: Time is up for contact.

10-30: Does not conform to FCC rules.

10-31: Not assigned.

10-32: I will give you a radio check.

10-33: Emergency traffic (rubberneckers).

10-34: Trouble at this station.

10-35: Confidential information.

10-36: The correct time is…

10-37: Wrecker needed at….

10-38: Ambulance needed at…

10-39: Your message was delivered.

10-40: Not assigned.

10-41: Please tune to channel…

10-42: Traffic accident at …

10-43: Traffic tie up at…

10-44: I have a message for you.

10-45: All units, please report.

10-46 – 10-49: Not assigned.

10-50: Break channel.

10-51 – 10-59: Not assigned.

10-60: What’s the next message number?

10-61: Not assigned.

10-62: Unable to copy, or use a phone.

10-63: Not assigned.

10-64: Not assigned.

10-65: Awaiting your message or assignment.

10-66: Not assigned.

10-67: All units comply.

10-68: Not assigned.

10-69: Not assigned.

10-70: Fire at…

10-71: Continue with the transmission in sequence.

10-72: Not assigned.

10-73: Speed trap at…

10-74: Not assigned.

10-75: You are causing interference.

10-76: Not assigned.

10-77: Negative contact.

10-78 to 10-82: Not assigned.

10-84: My telephone number is…

10-85: My home address is…

10-86 to 10-90: Not assigned.

10-91: Talk closer to the microphone.

10-92: Your transmitter is acting up.

10-93: Check my frequency.

10-94: Please give me a long count.

10-95: Transmit dead carrier for 5 seconds.

10-96 To 10-98: Not assigned.

10-99 Mission completed.

10-100 Need to go to the bathroom.

10-101 to 10-199: Not assigned.

10-200: Police needed at…

These days, you don’t need a CB radio to say “10-4.” The phrase has entered the mainstream lexicon and can be used by anyone, regardless of whether they’re a trucker or not. So next time you hear someone say “10-4,” you’ll know exactly what they mean.

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