Abstract: Two sensors 2, 3 are provided for detecting an interception object on respective different surfaces of device housing 1 of a portable radio device. Two antennas 4, 5 are provided in the state of having directivity in respective different directions in device housing 1. Also provided are switching unit 8 for selectively connect antenna 4 or 5 to transmit-receive unit 7 and control unit 6 for controlling the same. Detection signals of respective sensors 2, 3 are applied to control unit 6 in the state that device housing 1 is fitted to a human body, the fitting direction of device housing 1 is determined through the detection signals, and switching unit 8 is controlled such that one of antennas 4, 5 on the side not contact with the human body is selected.

Abstract: A mobile communication system includes a one-way communication system where a wide area base station forms a wide one-way communication area and a two-way communication system having a cellular service area which is formed by a plurality of cell base stations each forming a cellular two-way communication area. A mobile terminal can communicate with the one-way communication system and the two-way communication system. Further, a system controller connected to the one-way communication system and the two-way communication system controls mobile communications in the wide one-way communication area and/or the cellular service area. The system controller transfers data addressed to a mobile terminal to the mobile terminal through a selected one of the one-way communication system and the two-way communication system.

Abstract: A mobile communication apparatus includes a wide area receiver and a cell transceiver. The wide area receiver which is operable at relatively low power receives a selective calling signal from a wide area base station that forms a wide one-way communication area. The cell transceiver operable at higher power than the wide area receiver performs two-way communication with a nearest cell base station that forms a two-way communication area. The wide area receiver is caused to operate at all times. However, when the mobile communication apparatus exists outside the wide one-way communication area, the transceiver is caused to start operating.