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Set-top Boxes

of enhanced functionality. It would also require a backward signaling path from each TV to the RG to allow channel changing, and a method of setting priorities and avoiding conflicting signaling in the backwards path (to prevent two user at two separate TV sets from trying to change the channel on a given network at one time).

The introduction of set-top boxes somewhat further complicates the issue. In some CATV networks the set-top box is used as an addressable device and in others it is used to merely augment the tuning capabilities of a non-cable ready TV. In the addressable situation, this function is a unique capability provided by the set-top box and it must be provided (possibly by a special interface card). Taking this approach will eliminate the set-top box and it will allow easy access of the selected output channel to the RG (as an input) so that the selected channel can be routed for availability to any sub- tending video device (TV, VCR, computer video capture card, etc.) As noted above this approach will require the development of a signaling capability from the end devices back to the RG, but the payoff in greatly added flexibility could easily be worth the price of overcoming that issue.

In other CATV networks, the set-top box only provides a tuning function for video receiving devices that are not cable ready. In this tuner function, the set-top box adds no complexity to the RG, but th set-top box merely becomes part of the TV or, the set-top box could be replaced by the tuning capability of interface modules with that function. The selection of the approach to be taken should be determined by the individual circumstances of a given end-user.


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