All backplanes and sockets provide four screw terminals per channel for all field connections. These connections satisfy all transducer inputs, process current outputs and provide transducer excitation when necessary. A cold junction temperature sensor (model AC1361) sensor is also supplied on each channel to accommodate thermocouple input modules. A pair of pin sockets permits installation of the AC1362 current sensing resistor used with the 5B32 current input module. All 5B Series backplanes and sockets require a regulated +5 Vdc external power source.