Environmental control system with auxiliary control interface

An environmental control system for the severely disabled provides a "pass through" mode that allows a system output to mimic or emulate a user controlled switch input. The pass through mode permits a single user controlled switch to be shared among multiple systems for the disabled. In the normal mode, the user controlled switch controls various control functions provided by the environmental control system. In the "pass through" mode, the environmental control system operates "transparently" and passes the switch closures through to an electronically-controlled switch that appears electrically like a manually actuated switch to control other equipment for the disabled. The pass through mode is exited upon user actuation of the user controlled switch for more than a programmed time period and/or automatically upon occurrence of certain events (e.g., telephone ringing detection).