Patent ID: 6995653

Claim:
A vehicle-mounted device communication controller which includes a vehicle-mounted unit for communicating with a plurality of ID-registered portable units and a controlled equipment installed in a vehicle, and in which first and second search signals and first and second response signals are sent and received between the vehicle-mounted unit and the plurality of portable units, one of the plurality of portable units is authenticated from among the plurality of portable units by the vehicle-mounted unit, and the controlled equipment specified by the authenticated portable unit is controlled, wherein the vehicle-mounted unit includes a controller which changes a setting of a search method of portable units between a simple search method which is based on sending/receiving of the first search signals and the first response signals and an individual search method which is based on sending/receiving of the second search signals and second response signals to determine the presence of at least one of the plurality of the portable units and establish a communication between the present portable unit and the vehicle-mounted unit, and an ID-storage unit which updates and stores an ID of one of plurality of the portable units authenticated at a latest time as a latest authenticated ID, and when the latest authenticated ID is stored in the ID-storage unit, the controller searches for the portable unit having the latest authenticated ID using the individual search method starting with the second signals corresponding to the latest ID authenticated portable unit, and wherein, in the simple search method, the authentication is sequentially performed on the plurality of portable units.