Program and System Information Protocol

The Program and System Information Protocol is the protocol used in the ATSC digital television standard for carrying data about each channel. It defines virtual channels and content ratings, as well as program guides with titles and descriptions. It also sends the exact time referenced to UTC, the station ID, and conditional access information. PSIP is defined in ATSC standard A/65A.

Included tables

• STT (system time table)* - current time, once per second, within ±4
• MGT (master guide table)* - data pointers to other PSIP tables
• VCT (virtual channel table)* - assigns numbers to each channel
• RRT (rating region table)* - content ratings for each country
• EIT (event information table)* - titles and program guide data
• ETT (extended text table) - detailed descriptions of channels and programs
• DCCT (directed channel change table) -
• DCCST (directed channel change selection code table) -

* indicates a US FCC requirement

The DCC function lets broadcasters tell a DTV receiver where to change, based upon the viewer's settings. This is most likely to be a ZIP or other postcode, which can select demographically-based programming to show, such as TV commercials or weather bulletins, possibly taken from an accompanying datacasting channel.

Implementation of this feature is entirely optional, and depends on development of receiver/decoder technology. For example, a PVR-like computer memory device could record commercials broadcast at other times for later replay, so that many more different commercials could be shown in different parts of a large metro area than can actually be transmitted at once.

External link

• http://www.PSIP.org