Abstract: A communication apparatus for controllably bidirectionally transferring information between a vehicle and a docking station advantageously utilizes pulsed radiant energy for effecting the information transfer. A first radiant energy emitting device and a first radiant energy detecting device is located on the vehicle and a second radiant energy emitting device and a second radiant energy detecting device is located on the docking station. A first frequency control device recieves electrical signals from the first radiant energy detecting device, produces pulse control signals having a nominal frequency which is variable within a predetermined frequency range, and controllably delivers the produced pulse control signals at the nominal frequency to the first radiant energy emitting device located on the vehicle.

Abstract: Seat switches for detecting the presence and absence of an occupant in the seat of a vehicle are commonly used on industrial and commercial vehicles. It is desirable that the control signal produced by such seat switches be responsive only to the presence and absence of the vehicle occupant, and be relatively simple, rugged, and inexpensive. The instant invention includes an emitting device for directing a source of coded radiant energy across a vehicle seat, and a detecting device for receiving radiant energy, including a portion of the coded radiant energy in response to the seat being vacant. The detecting device produces an electrical signal in response to the received radiant energy. An electrical circuit produces a control signal only in response to the detecting device receiving the coded radiant energy.