Police radio 10-codes are numeric communication signals used by law enforcement and government agencies to help reduce confusion during two-way voice radio communication, according to eInvestigator.com. Private citizens who use citizen band radios and listen to police radio scanners also use police 10-codes.
The Association of Public-Safety Communications Officials published the first 10-codes in 1940 as an aid to reduce the amount of speech broadcast over police radios and to add privacy to communication, notes eInvestigator.com. There is no uniform standard for the codes, and the meaning behind the codes can vary by jurisdiction thereby causing confusion. As a result, agencies such as the United States Federal Emergency Management Agency and U.S. Department of Homeland Security discourage their use.