Why do cops use 10 codes?


Editorial team Published on

Police use 10-codes primarily to save airtime and ensure the most important parts of a message are heard over older or choppy radio equipment.

Technical and Historical Reasons

  • Overcoming Radio Delay: Early two-way radios required a brief moment to warm up or engage fully after an officer pressed the transmit button. Starting a transmission with the word "10" acted as a buffer syllable, ensuring the actual meaning that followed wasn't cut off.
  • Brevity and Airtime: Radio channels were limited and shared by many officers. Short numeric codes reduced the time needed to speak, keeping channels clear for other emergencies.
  • Standardization: Developed largely between 1937 and 1940 by the Association of Public-Safety Communications Officials (APCO), these codes provided quick, uniform ways to share common statuses (like 10-4 for acknowledgement or 10-20 for location).

Privacy and Modern Usage

  • Basic Privacy: Historically, codes provided a layer of operational security so that casual listeners with basic radio scanners could not immediately understand sensitive details.
  • Current Shift to Plain Language: Since 2006, many federal and local agencies have moved toward plain English communication to avoid confusion, especially when multiple different departments work together during major multi-agency responses. However, many local departments still rely on familiar codes due to tradition, cost, or existing dispatch software.