Originally, in the US, many (if not most) broadcast licensing authorities required a licensed board operator to run every station at all times, meaning that every DJ had to pass an exam to obtain a license to be on-air, if their duties also required them to ensure proper operation of the transmitter. This was often the case on overnight and weekend shifts when there was no broadcast engineer present, and all of the time for small stations with only a contract engineer on call.

In the U.S., it was also necessary to have an operator on duty at all times in case the Emergency Broadcast System (EBS) was used, as this had to be triggered manually. While there has not been a requirement to relay any other warnings, any mandatory messages from the U.S. president would have had to first be authenticated with a code word sealed in a pink envelope sent annually to stations by the Federal Communications Commission (FCC).

Gradually, the quality and reliability of electronic equipment improved, regulations were relaxed, and no operator had to be present (or even available) while a station was operating. In the U.S., this came about when the EAS replaced the EBS, starting the movement toward automation to assist, and sometimes take the place of, the live disc jockeys (DJs) and radio personalities.

Early analog systems

In television, playout automation is also becoming more practical as the storage space of hard drives increases. Television shows and playout automation is also becoming more practical as the storage space of hard drives increases. Television shows and television commercials, as well as digital on-screen graphics (DOG or BUG), can all be stored on video servers remotely controlled by computers utilizing the 9-Pin Protocol and the Video Disk Control Protocol (VDCP). These systems can be very extensive, tied-in with parts that allow the "ingest" (as it is called in the industry) of video from satellite networks and electronic news gathering (ENG) operations and management of the video library, including archival of footage for later use. In ATSC, Programming Metadata Communication Protocol (PMCP) is then used to pass information about the video through the airchain to Program and System Information Protocol (PSIP), which transmits the current electronic program guide (EPG) information over digital television to the viewer.

See also