By Mark K. Eyer, General Instrument Corporation
In anticipation of North American broadcasters commencing digital transmissions in 1998, digital television standards work continued in earnest in 1997. In December, the Advanced Television System Committee (ATSC) adopted its newest standard, A/65, Program and System Information Protocol for Terrestrial Broadcast and Cable [(4)]. The ballot approval culminated over twelve months of work in the ATSC’s T3/S8 Transport Documentation Specialists subcommittee with help from the Society of Cable Telecommunications Engineers (SCTE) Digital Video Subcommittee (DVS), where the standard was also approved by letter ballot in January. The acceptance of A/65 for use with both terrestrial broadcast and cable transmission media is a triumph for cooperative efforts in standards-setting and will facilitate interoperability between broadcast and cable as we move into the age of digital transmission. This paper describes the new A/65 standard, beginning with the system functional requirements upon which it was based. An overview of the protocol is presented to give the reader a flavor of the features it provides. The relationship of A/65 to the prior ATSC standards for program guide and System Information, A/55 and A/56 respectively, is discussed. Finally, the use of A/65 on cable is explored.