For example, if you ask someone, “[Callsign you’re calling], can you keep an eye out for dangers on the road ahead?” and someone replies, “10-4, anything in particular you’re worried about?” you might say, “Thanks. I’ve got a tire with low pressure, so anything that might pop a tire, over. ” If all the other person says is, “10-4,” you don’t need to say anything. You can say, “10-4, over” if you’d like to let them know you’re done speaking if you’d like.
In a professional setting (i. e. you work as a truck driver), you’d know if someone is messaging you when they reference your callsign. You do not need to reply to general messages that don’t concern you or aren’t addressed to you specifically.
A 10-4 on its own would signal that you’re accepting the request, just to be totally clear.
If you did want to end the conversation, you would say, “10-4, out. ” This means you understand what they said and you’re getting off of the radio or leaving. You never actually say “over and out” if you’re using a proper CB channel. You can totally use it casually, though! In more laid back environments, “10-4, Rodger” can be used in place of “10-4, over. ”[6] X Research source
“Plain English” is the alternative to ten codes. If people are using regular conversational English over the radio, they’re using plain English. You don’t need to use “10-4” if people are using plain English. [8] X Research source
10-1, which means “I’m having trouble hearing you,” and 10-2, which means, “you’re loud and clear. ” 10-6, which is a kind way of saying, “I’m busy, please leave me alone. ” 10-13, which is used to signify a weather report or road conditions update is coming up. 10-20, which is means, “My location is currently…”
