How Does a Cable TV Box Work?

From the Network to the Cable Box

Cable companies receive satellite signals from providers that are then routed to their processing centers. Companies like Comcast, Time Warner and Cox Communications break the signals out into channels of programming. The video signals are compressed and sent out from their centers to customers.

What Happens Inside of the Box?

The video sent along the coaxial cable is received and decoded based on the channel called up by the viewer. The box converts the signal from its compressed state and ships the signal to the screen. As the user changes channels, the box calls up the next video signal, decompresses it and sends the feed to the TV.

How Does the Box Know What to Show?

Coaxial cables are not the only wires running to the converter box. A phone line is also connected to the box. This facilitates communication to and from the box. When a user changes his level of programming, the cable company sends a transmission to the customer's cable box that reveals new channels or takes discontinued ones away. When that customer orders a pay-per-view movie, a telephone signal is sent to the cable company. This signal permits the movie to be transmitted to the user's cable box.