| 摘要 |
A telephone system in which the user carries a handset which operates both as a mobile telephone when away from a home base station through a cellular radio network, and the handset automatically initiates operation of a land based line system when located at or near to a home base station. The initiation of the land base station may alternatively be set up by a unit separate from the handset and carried by the user or when the handset operates as a mobile telephone it transmits low power narrow bandwidth telemetry signals adapted to identify the handset. The homebase station may include reception means for the low power narrow bandwidth telemetry signals, signal interpretation means and signal response means. The interpretation means provides an output signal when the identifying signal from the handset, signal interpretation means and signal response means. In a second operating mode incoming calls to the handset may be routed through the PSTN system. The identifying signal may be an infra-red or an ultrasonic signal. The land base station can transmit low power identity signals so that when a handset receives the identity signals it transmits a confirmation signal and the land base station switches the handset signals to the second operating mode. In one embodiment the operation of the land based line system is initiated when the handset is detected by its presence in a charging station. In an alternative embodiment the operation of the land based line system is initiated when the handset is identified by recognition of the code signals used for calling and maintaining affiliation with a cellular radio network. |
