ATSC A/55 Program Guide For Digital Television

The idea behind the ATSC A/55 specification was one of the least-thought-out ideas ever found in digital television. Basically, the idea was that terrestrial broadcasters and cable television systems would want to electronically publish their program schedules using a version of the same technology used for DirecTV and General Instrument's Digicipher/Digicipher II electronic program guide.

The result was a document that was virtually impossible to use, that would have resulted in broadcasters and cable systems using a sole vendor -- General Instruments, now a division of Motorola, Inc -- for provisioning, and which employed many bits of information to provide limited useful information about what was being shown on a television or cable television channel. In addition, the specification didn't cover many of the real 'goodies' behind the electronic program guide used by DirecTV, including providing the data so that users could, for example, tell their interactive program guide to flag all content that was directed by the director Bertrand Blier.

There is an erroneous belief that U.S. patent 6,115,074 embodies much of the technology exposed in ATSC A/55. This is largely believed by persons who either have read the patent and the specification but lack the technical expertise to compare the claims to the specification, or who have never read either, or lack technical expertise to understand either.

While ATSC A/55 might have been included in some early U.S. digital television sets, as a practical matter, few to no broadcasters or cable systems ever transmitted using the A/55 technology.

On very special order and with a non-trivial amount of effort, EtherGuide Systems can provide a unit that will transmit A/55 bit streams.

In September, 2006, the ATSC withdrew ATSC A/55, which had been supplanted by difficult, but much easier to implement PSIP specification, ATSC A/65 almost a decade earlier. A/65 was designed to answer the actual needs of broadcasters and cable system operators, and much of the satellite aspects of A/55 were moved to ATSC A/81.

See: ATSC Standards