Electronic Program(me) Guide (EPG)
or also an Interactive Program(me) Guide (IPG)
or Electronic Service Guide (ESG),

is an on-screen guide to scheduled broadcast television programs, allowing a viewer to navigate, select, and discover content by time, title, channel, genre, etc, by use of their remote control, a keyboard or even a phone keypad.

http://en.wikipedia.org/wiki/Electronic_program_guide

Hidden signals: Captioning | Teletext | CGMS-A | GCR | PDC | VBI | VEIL | VITC | WSS | XDS

digital EPG services
create and drive your own EPG http://www.tvbrowser.org/

study ZUI http://www.opentv.com

analog EPG services
http://www.bds.tv/
http://nxtvepg.sourceforge.net/intro.html

PVR DVR Solutoins I am investigating include the following ::.

MythTV http://www.mythtv.org/

QAM    http://en.wikipedia.org/wiki/QAM_tuner