Casio Computer Co., Ltd.

Naruhiko Sakamoto

Shinjiro Ishida

A radio telephone system is comprised of a communication network, a cordless telephone apparatus and a plurality of public radio base stations, both being connected to the communication network, and a handset unit of the cordless telephone apparatus is capable of exchanging messages with the plurality of public radio base stations. The cordless telephone apparatus is provided with a control-data storage unit for storing data of controlling handsets unit belonging to the cordless telephone apparatus. The control-data storage unit stores data each comprising a combination of an extension number and a phone number of a handset unit. The cordless telephone apparatus judges whether a handset unit to be reached is in a service area of the apparatus, when the handset unit is called from another handset unit of the cordless telephone apparatus. When it is determined that the handset unit to be reached is not in the service area, the cordless telephone apparatus makes an outside-line calling based on the phone number stored in the control-data storage to reach the handset unit through the public radio base station.

Method and apparatus for calling a handset unit in radio telephone system

In a cordless telephone system, a radio communication unit is detachably connected to a base unit of the cordless telephone system. While the radio communication unit is electrically and physically separated from the telephone base unit, and brought out from a home or a firm, a radio communication is established between the radio communication unit and a telephone mobile unit, but also between the telephone mobile unit and a telephone subscriber via the base unit. Thus, an outdoor type telephone mobile unit is available in the cordless telephone system.

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Tokyo, Japan

Naruhiko Sakamoto