An interface connector device for interconnecting a plurality of input/output devices including a signal bus connected to a control and to the input/output devices for multiplexing the signals between the control and the input and output devices, the bus interconnecting a plurality of interface and connector devices, and each of the interface and connector devices including address recognition circuitry as well as programmable configuration selection logic to configure the connector device to respond to a variety of input/output devices. In addition, the signal bus and connector devices are adapted to recognize and convey various levels of signals, for example, different voltage levels representing control information, framing signals, and diagnostic command signals.