| 摘要 |
A cellular telephone (10) having transmit and receive channels with a digital-mode communication capability includes also a memory (76) and switching circuitry operative under control of a microcontroller (28). The switching circuitry enables connection of input and output ports (78,80) of the memory (76) to either one of the channels. By entry of commands to the microcontroller (28), the microcontroller (28) arranges the configuration of the switching circuitry to permit storage in the memory (76) of a message originating locally from a user of the telephone (10), inputted via a microphone (12) connected to the transmit channel, or from a distant telephone connected via a communication link to the receiving channel. Subsequent playback of the message from the memory (76) may be coupled via the switching circuitry to a speaker (14) of the telephone (10) to be heard by a user of the telephone (10), or may be outputted to the transmit channel for communication to the distant telephone. Preferably, the message is stored in compressed format to save memory space. Compression may be provided by compression circuitry (42) in the transmit channel in the event of an inputted analog protocol message from the distant telephone. Playback may be accomplished by way of expansion circuitry (44) of the receive channel. This enables the telephone (10) to provide features of prompt, voice pad, transcription, and voice mail. In addition, a reduction on a data sampling rate, in response to the condition of a battery charge, permits an extended period of operation of the telephone (10) prior to the termination of adequate battery voltage. <IMAGE> |
