Patent ID: 8220750

Claim:
A power drive unit (PDU) for an air cargo loading system in which a controller is connected to a plurality of such PDUs via a wired network and is instructed via wireless remote handset to activate one or more of said PDUs in response to a coded light signal, the PDU comprising: a light source configured to emit light; at least one light detector configured to receive light; and a PDU processor coupled to said at least one light detector and programmed to: take into account ambient light to determine whether a Unit Load Device (ULD) is overhead, based at least in part on reflected light received by said at least one light detector after illuminating an underside of the ULD by said light source; determine whether a coded light signal received by said at least one light detector comprises a command signal to be provided to the controller; and output an appropriate first command information signal, if the coded light signal is determined to be a command signal.