Connecting a cable set top box (STB) to a personal computer (PC) is fairly straightforward, providing the PC has a device that allows it to receive digital television signals -- a digital TV tuner -- installed.
TV tuners come in two basic forms, internal and external. Internal TV tuners are typically cards that must be installed inside your computer, while external TV tuners typically plug into a universal serial bus (USB) port.
Assuming that your set top box is already connected to the cable source at the wall jack, connecting the box to your PC involves running a cable from the cable output jack on the box to the input jack on the TV tuner. If you have more than one TV tuner, each tuner needs its own TV signal; you can split the cable signal from the wall jack with a cable splitter, if necessary.
Aside from the physical cable connection between the set top box and the TV tuner inside, or attached to, your PC, you need some software -- and possibly some additional hardware -- to control the way TV pictures are displayed and to change TV channels. In some cases, you can attach a remote control that allows you to change channels directly from your PC.