PORTABLE TELEPHONE SET AND RADIO CHANNEL DESIGNATION METHOD

PURPOSE:To make dialing through a private radio base station offering less expensive talking charge when the portable telephone set is able to use a public radio base station and the private radio base station. CONSTITUTION:A control section sets a frequency of a 1st control carrier for a private use as an oscillation frequency of a synthesizer (S1). Then whether or not an ID code of a radio base station for a cordless telephone set to which the portable telephone set belongs is detected from the control carrier is discriminated (S2). When the ID code of the radio base station for the cordless telephone set to which the portable telephone set belongs is detected, after the synchronization with the signal transmission of the radio base station, the mode enters the reception standby mode in which the maintenance of synchronization, call reception or dialing is repetitively executed (S7, S8, S9) and respective processing to an event of the call reception or dialing is executed (S15, S16). On the other hand, when no ID code is detected as the result of searching all control carriers for the private use, the frequency of the public control carrier is set to the frequency of the synthesizer (S10) and after the setting of synchronization, the mode enters the reception standby mode.