Suffice it to say that it is a challenge to get different digital devices to communicate effectively on a single set of wires. In order to avoid reinventing the wheel every time a new computer or new device is introduced, hardware designers make up a list of characteristics regarding their bus and what can connect to it. We call such a standard a bus architecture. Up till recently, every vendor has its own bus architecture. A few of them are Massbus, Microchannel, Omnibus, Q-bus, Multibus and S-100 bus.