Sun Microsystems 220R manual About the Serial Ports

About the Serial Ports

The system provides two serial communication ports through a pair of DB-25 connectors located on the back panel. Both ports are capable of synchronous and asynchronous communication.

In synchronous mode, each port operates at any rate from 50 Kbaud to 256 Kbaud when the clock is generated internally. When the clock is generated from an external source, synchronous communication occurs at rates up to 384 Kbaud.

In asynchronous mode, either port supports baud rates of 50, 75, 110, 200, 300, 600, 1200, 1800, 2400, 4800, 9600, 19200, 38400, 57600, 76800, 115200, 153600, 230400, 307200, and 460800 baud.

Both serial ports can be configured to provide EIA-423 or EIA-232D signal levels. Signal levels are controlled by jumpers located on the system’s main logic board. The default setting is EIA-423. For more information about configuring the serial port jumpers, see the Sun Enterprise 220R Server Service Manual.

See “Reference for the Serial Port A and B Connectors” on page 157 for the connector diagram, back panel icon, and pin assignments.

Chapter 4 Hardware Configuration 79