AT&T 3B2/300 Technical Reference Manual page 450

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CM195AY EPORTS CARD
General
The CMl 95A Y Enhanced Peripheral Port Controller (EPORTS) Card provides eight separate,
asynchronous serial ports (RS-232C). Functionally, the EPORTS card consists of the Common
Input/Output (CIO) circuits, and four Serial Communication Controllers (SCCs). The Serial
Communication Controllers function as Dual Universal Asynchronous Receiver/Transmitter (DUART)
circuits. The eight asynchronous serial ports are identified as subdevices. DUART O (SCC 0) supports
subdevices SDO and SD1; DUART 1 (SCC 1) supports subdevices SD2 and SD3. DUART 2 (SCC 2)
supports subdevices SD4 and SOS; DUART 3 (SCC 3) supports subdevices SD6 and SD7. Drivers and
receiver circuits are used to interface the DUARTs to MODEMS and/or data terminals (RS-232C).
Figure 3-61 is a functional block diagram of the CM195Y EPORTS Card.
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