Abstract: A communications terminal for use with a programmable controller to permit transmission of status and control information between that programmable controller and a plurality of programmable controllers having similar communications terminals associated therewith and connected in a communications loop. The communications terminal permits one programmable controller to utilize signals originating in other programmable controllers and to provide asynchronous time division multiplexed signals to other programmable controllers via a shielded, twisted-pair conductor to control devices connected to those other programmable controllers.

Abstract: A reconfigurable serial loop multiplex communication system for communication of digital and analog status and control information between field terminal locations or to a central control location via a twisted pair line. Input modules in a first terminal station communicate signals received at their input to output modules having the same byte address in other terminal stations. At the central control locaton, signals from an input module may be readdressed for communication to output modules having a different byte address.