Sughrue, Mion, Zinn, Macpeak & Seas, PLLC
Vehicle-mounted device with sleep function for use in road-to-vehicle communication system
 There is disclosed a vehicle-mounted device with a sleep function for use in a road-to-vehicle communication system. After having indicated a switching period T.sub.1 and reception frequencies F1, F2 to a frequency switching controller, a controller stops operation of an internal counter, and enters a sleep mode until it cancels the sleep mode in response to a detected signal from a receiver. While a vehicle with the vehicle-mounted device is running outside of a communication range of a road radio unit installed at a toll gate or the like, the frequency switching controller independently performs a frequency search process on an RF module, and the controller is in the sleep mode. Therefore, the vehicle-mounted device has a relatively low power requirement. 
NEC Corporation
G
G07B
inventional
Hiroshi
Yamashita