Common Circuitry: The Pooled Modem common circuitry that includes all circuitry shown on Figure
Conversion Resources: The two conversion resources (port circuits) are identical and each contain the following:
●Microprocessor
● Transmit and Receive
● Universal Synchronous/Asynchronous Receiver and Transmitter (USART)
●Data USART Clock (DUCK)
●Digital Signal Processor (DSP).
The microprocessor controls an
The DUCK and TRIC interface
The USART interfaces the serial data stream of the DUCK to the conversion microprocessor. The USART can be programmed by the microprocessor to operate synchronously or asynchronously. T h e U S A R T a l s o d o e s t h e f o l l o w i n g t a s k s f o r t h e p o r t c i r c u i t microprocessor:
●Appends start and stop bits to parallel data received from the microprocessor in the asynchronous mode
● Converts serial data received from the DUCK to parallel data
● Buffers data in both directions
●Detects and generates break characters.
The DSP provides modem emulation. It interfaces the port circuit signal and the remote modem. The microprocessor directs the DSP to execute one of many programs. The DSP produces data, carrier detection, and timing information for the port circuit microprocessor.