About Serial Ports - Sun Microsystems Fire V890 Service Manual

About Serial Ports

The system provides two serial communication ports through a single, shared DB-25
connector located on the rear panel. The primary port is capable of both
synchronous and asynchronous communication, while the secondary port is
asynchronous only. In synchronous mode, the primary 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, the synchronous port operates 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.
The primary port is accessible by connecting a standard serial cable to the rear panel
serial port connector. To access the secondary port, you must attach a serial port
splitter cable (Sun part number X985A) to the rear panel serial port connector. The
connector labeled "A" on the splitter cable provides the primary port; the connector
labeled "B" provides the secondary port.
You can configure both serial ports to comply with the Electronics Industries
Association EIA-423 or EIA-232D standards using jumpers located on the system's
I/O board. The jumpers are factory-set for the EIA-423 standard, which is the default
standard for North American users. Compliance with the EIA-232D standard is
required for digital telecommunication in nations of the European Community.
For more information about configuring the serial port jumpers, see "About Serial
Port Jumpers" on page 241.
See "Reference for the Serial Port A and B Connectors" on page 298 for the connector
diagram, rear panel icon, and pin assignments.
238 Sun Fire V890 Server Service Manual • October 2005