The electronic fee collection (ETC) system based on radio communication technology allows vehicles travelling along the toll road to follow the toll payment procedure automatically without coming to a stop when they pass through the toll gate. Research activities are vigorously being promoted on this system. In order that the ETC system may effectively function in such an application, the on-board equipment must be provided with the data processing system containig the central processing unit (CPU) which can process the toll data very rapidly. One of the problems that remain to be solved is an excessive power drain from the on-board battery because the data processing system is operating even when the vehicle is running in the areas other than the entrance or exit of the toll gate. This condition prevails despite the fact that the related data must quickly be processed only during limited time and in narrow space while it is passing through the gate. The power management function that can suspend the operation of the data processing system except when the toll is being collected has been developed. Adapted to the ETC system, this function is expected to solve the foregoing problem and achieve significant power consumption. A description of its details is given below. (A*)
Abstract