Be careful when buying network cables as there are two types. Most are wired straight through and it's these that are used to connect PCs, servers, printers and other devices to switches. Such cables are often called 'patch' cables, but you can also get 'crossover' leads, which can be used to network two PCs together without a switch.

Many modern switches can detect the type of cable and work with either, but not all. So if you're having problems, first check the type of cable: retail crossover leads usually have this information stamped on the plastic sheathing.