10 codes are used in CB Radio transmitting to quickly relay information. The most commonly known ones are "10-4", meaning OK, and "What's your 20?" meaning "Where are you?" You can hear some of these codes in the song Convoy.
My favorite is 10-100.
10 codes may vary by location in the U.S. or world - there are regional dialects. Most of the countries that know them are English-speaking. Q codes are more internationally known, for CB, ham radio, and other amateur radio enthusiasts.
10-0 - Caution
10-1 - Weak signal
10-2 - Good signal
10-3 - Stop transmitting
10-4 - Affirmative, OK
10-5 - Relay message to .....
10-6 - Busy
10-7 - Out of service
10-8 - In service
10-9 - Repeat transmission
10-10 - Transmission complete, standing by
10-11 - Talking too fast
10-12 - Stand by, visitors present
10-13 - Advise of existing conditions
10-14 - Message, information
10-15 - Message delivered
10-16 - Reply to message
10-17 - Enroute
10-18 - Urgent
10-19 - Contact, in contact with
10-20 - Location
10-21 - Contact ______ by phone
10-22 - Disregard
10-23 - Arrived at scene
10-24 - Assignment completed
10-25 - Report to, meet
10-26 - Estimated arrival time
10-26- Disregard Last Information/Cancel Last Message/Ignore
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
10-32- I will give you a radio check
10-33- Emergency Traffic at this station
10-34- Trouble at this station, help needed
10-35- Confidential Information
10-36- Correct Time is .........
10-38- Ambulance needed at .........
10-39- Your message delivered
10-41- Please tune to channel ........
10-42- Traffic Accident at ..........
10-43- Traffic tieup at .........
10-44- I have a message for you (or .........)
10-45- All units within range please report
10-50- Break Channel
10-62- Unable to copy, use phone
10-65- Awaiting your next message/assignment
10-67- All units comply
10-70- Fire at .......
10-73- Speed Trap at ............
10-75 -You are causing interference
10-77 -Negative Contact
10-84 -My telephone number is .........
10-85 -My address is ...........
10-91 -Talk closer to the mike
10-92 -Your transmitter is out of adjustment
10-93 -Check my frequency on this channel
10-94 -Please give me a long count
10-95 -Transmit dead carrier for 5 sec.
10-99 -Mission completed, all units secure
10-100 - Need to go to bathroom
10-200 - Police needed at ..........