| 摘要 |
An accessory apparatus for mobile radio telephones, particularly those used in cellular networks, permits utilization of the full communication range capability of a vehicle-mounted cellular radio telephone by a cordless portable handset remote from the vehicle. The apparatus includes a plug-in adapter unit located in a vehicle and interconnected between the existing handset and transceiver of the vehicle-mounted radio telephone. The adapter unit includes a first, resident, down-link transceiver operating at radio frequencies outside of the cellular frequency band, and adapted to receive demodulated audio and/or data signals from the resident cellular transceiver, and retransmit the signals via a low-power modulated down-link RF carrier signal to a portable remote cordless handset/transceiver. The cordless handset has a keypad, speaker, microphone and transceiver which receives down-link transmissions from the adapter unit transceiver, and transmits voice or data signals via a low-power up-link carrier signal to the adapter unit transceiver, which demodulates the information signals from the up-link carrier signal, and conveys them to the existing radio telephone transceiver for transmission at high power to the cellular network.
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