About The Serial Ports - Sun Microsystems Enterprise 250 Owner's Manual

About the Serial Ports

The system provides two serial communication ports through a pair of DB-25
connectors located on the rear 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 "About Serial Port Jumpers" on page 64.
See "Reference for the Serial Port A and B Connectors" on page 264 for the connector
diagram, rear panel icon, and pin assignments.
60 Sun Enterprise 250 Server Owner's Guide • June 1998