| 摘要 |
<p>A portable communications device (200) and accessory system which provides full-duplex asynchronous communications between a portable communication device (200) and external accessories (214) over a synchronous digital interface (215). The system includes a digital signal processor (208) for generating a first synchronous digital voice signal, a UART (232) for generating a first asynchronous data signal, and a microprocessor (210) for generating a synchronous control command signal. The system further includes a first multiplexer (236) for multiplexing the first synchronous digital voice signal and the first asynchronous data signal and the synchronous control command signal onto an interface line (215). The interface line couples the communication device to the at least one external accessory (214). A second multiplexer (242) is coupled to the interface line (215), for routing the first synchronous digital voice signal and the synchronous control command signal to the at least one synchronous internal device (217), and for routing the first asynchronous data signal to the asynchronous internal device (230).</p> |
