The network is connected by four core twisted pair cable which may be up to 1 kilometre long. The use of a differential signal on twisted pairs reduces the amount of radiation from the cable and increases the noise immunity of the system. For short networks inexpensive unsheilded cable such as 4-core signal cable available from RS components is suitable, for longer networks a sheilded cable such as BICC type CS7219 is recomended. Connection to the cable is via standard 5 pin, 180 deg DIN connectors with the following pin assignments: -
Pin1 Data +ve Pin4 Data -ve Pin2 Common Ov Pin5 Clock +ve Pin3 Clock -ve
The wires from each station are wired in parallel to the network using connectors where convenient. Eurocard stations will generally have a DIN socket mounted on a front panel whilst the ATOM station will have either a DIN socket mounted on the rear of the case bottom or a flying lead terminated in a DIN plug. The cable may go between stations in any order and by any route as long as there is only one path between any two stations. Any discontinuity in the wire such as branches of the wire or the end of the cable may cause reflection and degradation of the signal. For this reason larger or faster networks should be wired electrically in one long line, without spurs or branches, and the ends should be correctly terminated. Shorter networks may have spurs on them, for instance sockets may be networked around a room with a flying lead (spur) from each computer to its socket.