| 摘要 |
A vehicle mounted mobile transceiver (11) communicates via a secondary mobile unit (51) with a short range portable unit (10). The portable unit (10) can be either a cordless microphone or a transceiver. The portable unit (10) allows a remotely positioned operator to transmit messages to a base station (13). To ensure security and reliable operation, the portable and vehicle mounted units use digitized codes for ID and instruction purposes. These codes are newly generated from time to time by the vehicle mounted unit and are imparted to the portable unit via a battery charging interface. An improved remote squelch detect is also provided. The improved remote squelch detect substitutes the normal input to the vehicle primary mounted mobile transceiver (11) squelch gate for an audio signal. The remote squelch detect can then detect the presence or absence of this input signal at the output of the audio PA for the vehicle mounted mobile transceiver, and this detection can be used to enable the secondary mobile unit to repeat the incoming message to the portable unit. With less delay than the prior art methods.
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