About The Serial Ports; About The Parallel Port; About The Main Logic Board Jumpers - 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 92.
See "Reference for the Serial Port A and B Connectors" on page 277 for the connector
diagram, rear panel icon, and pin assignments.

About the Parallel Port

The system provides one IEEE 1284-compatible, bidirectional parallel port for
connecting the system to a local printer or other compatible parallel device.
Connectivity is provided by a standard 25-pin DB-25 connector on the rear panel
of the system. The parallel port operates at a 2-megabytes per second data transfer
rate and supports the EPP protocol modes as well as standard Centronics, Nibble,
and Byte modes.
See "Reference for the Parallel Connector" on page 279 for the connector diagram,
rear panel icon, and pin assignments.

About the Main Logic Board Jumpers

The jumpers on the main logic board have the following functions:
4 J2604 and J2605 are used to configure the serial ports for either EIA-423 or
EIA-232D operation. For information about the EIA-423/232D jumper settings, see
"About Serial Port Jumpers" on page 92.
Sun Enterprise 250 Server Owner's Guide ♦ Revision A, June 1998
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