Arrangement for sensing remote binary inputs

Abstract

An improved switch input arrangement for a system that remotely controls distributed electrical loads. The switch input arrangement is part of a transceiver decoder that receives commands from central controller for controlling the state of latching relays for controlling the power circuits of the loads. The improvements include: monitoring the state of contact closure inputs to the transceiver decoder, selectively enabling/disabling specific contact closures to control the masking of switch inputs, inclusion of an accumulated switch buffer to store the last actuation state of all relays, an answerback to insure that action occurs responsive to a switch input, a shifting threshold and multiplexing technique for more accurate reading of contact closure switch inputs, and the inclusion of a power-up reset message annunciated to the central controller to alert it that certain commands may have to be issued in order to reestablish the desired states of the transceiver.