Appendix B Signal Descriptions B-3
B.1.2 Serial Port A and B (RS-423/RS-232) Connectors

The serial port A and B connectors are DB-25 type connectors located on the

motherboard back panel. FIGUREB-2 illustrates the serial port A and serial port B

connector configuration and TABLEB-2 lists the connector pin assignments.

FIGUREB-2 Serial Port A and B Connector Pin Configuration
TABLEB-2 Serial Port A and B Connector Pin Assignments
Pin Mnemonic SignalName Description
1 Not connected None
2 TXD TransmitData Used by the data terminal
equipment(DTE) totransmit data
tothe data circuit equipment (DCE).
Except when controldata is being
sent, RTS,CTS, and DCD must be
ON for this line to be active.
3 RXD ReceiveData Used by the DCE in responseto
receiveddata from the DTE.
4 RTS Ready To Send Usedby the DTE to condition the
DCE for data transmission. The
transition to ON directsthe DCE to
go into transmit mode. The
transitionto OFF directs the DCE to
complete the transmission.
113
25 14
113
25 14
Serial port B
Serial port A