TV Guide has become the new industry standard to provide the mass market with a universal guide system anywhere in the US using your local over the air broadcast stations which are also carried on your cable system. QAM digital cable tuners are typically part and parcel of a product supporting TV Guide and can have a bearing on your experience setting up the feature.
When you first install the TV or other product with this feature you will prompted to setup the system by answering multiple questions. The system will then search out the cable system to locate the one or few other channels that carry the TV guide data. Often times this will be your PBS channel(s). After that has been accomplished if you are on cable the next time you turn on the product you will be asked to select your cable system. This creates the channel map for the product so the TV guide data matches channel number you are watching. During the year there may be updates to the channel map and/or content in which case you will turn on the product and be prompted to select your cable system again. Anytime you are asked to make this selection it will take another 24 hours to download and reconfigure the TV Guide function.
One important aspect of this free service is that the data is only down loaded when the product is turned off. Most DVRs using TV Guide provide an option to automatically turn off the unit sometime late at night that you are likely to be sleeping to insure your data is kept up to date for those who don