[jaycee]

The cable from the street is typically terminated in a brown box on the outside of the property. The "drop" as it's called is usually a multi pair cable for phone line(s) and a single RG58 coaxial cable. This is then split as required using splitters to run multiple points. Cable modems accept an RG58 feed the same as the STB does. In some cases, they will use more than one co-ax "drop" usually if the cable is too long or unable to run more than one device at once.

Sadly most telecomms companies will not connect to your own wiring (except for phone lines). This is because cheap coaxial cable/satellite cable doesn't usually work all that well for the high frequency signals that CATV systems use. This leads to SNR and signal level problems later on.

For the computer, you may be best running a CAT5 ethernet cable wherever you want it to go, and then have the cable modem sited near a coax point. Or have them use your STB for internet, so you will only need to site one coax point and one phone point. Run a cable from your phone sockets to wherever the entry point on the house will be, ie where they will be siting the master socket.