At least two standard (Cat-5) network cables were run to each room. All of them arrived back at a central patch panel in the garage. This arrangement allows any cable to be connected to any other cable.
The picture shows some connections made with yellow patch leads. Nick and Micky chose this colour to indicate that the connections are not for a standard computer network. In this case, the cables carry the Sky TV signal from the lounge to two of the bedrooms.
The red patch lead is for the Internet connection. It is coloured red as a reminder that the connectivity here is on the "wrong side" of the firewall and should be treated with respect! The blue patch leads are for standard connections between the router (at the top) and the various computers - and MP3 players around the house.
)