The standard development effort was started in the 1970s by the APCO, a trade association of mostly police and fire service providers.
[1][2] APCO-16 describes such characteristics and capabilities as: With the Federal Communications Commission's pending release of the first 800 MHz[note 1] band licenses, the LEAA funded a project to develop required capabilities and standards needed in trunked public safety two-way radio systems.
[2] The standards also gained acceptance in businesses such as Specialized Mobile Radio, utility communications systems, and refineries.
The result: three companies built APCO Project 16 compliant systems but radios from each manufacturer were incompatible with one another.
This program defined technical details such as "channel access time," "system growth capability," and "reliability.