I/O Ports and Connectors B-3address and allowable IRQ settings. It should also pro-vide instructions for readdressing the port and changingthe IRQ setting, if necessary.The built-in parallel port has autoconfiguration capabilitythrough the System Setup program. That is, if you set theparallel port to its automatic configuration and add anexpansion card containing a port configured as LPT1(IRQ7, I/O address 378h), the system automaticallyremaps the built-in parallel port to its secondary address(IRQ5, I/O address 278h). If the secondary port address isalready being used, the built-in parallel port is turned off.For more information, see “Parallel Port” in Chapter 4.For general information on how your operating systemhandles serial and parallel ports as well as for moredetailed command procedures, see your operating systemdocumentation.Serial Port ConnectorsIf you reconfigure your hardware, you may need pinnumber and signal information for the serial port connec-tors. Figure B-2 illustrates the pin numbers for the serialport connectors, and Table B-1 lists and defines the pinassignments and interface signals for the serial portconnectors.Figure B-2. Pin Numbers for the Serial PortConnectorsParallel Port ConnectorIf you reconfigure your hardware, you may need pinnumber and signal information for the parallel port con-nector. Figure B-3 illustrates the pin numbers for theparallel port connector, and Table B-2 lists and definesthe pin assignments and interface signals for the parallelport connector.Figure B-3. Pin Numbers for the Parallel PortConnector1 — 56 — 9Table B-1. Pin Assignments for the Serial PortConnectorsPin Signal I/O Definition1 DCD I Data carrier detect2 SIN I Serial input3 SOUT O Serial output4 DTR O Data terminal ready5 GND N/A Signal ground6 DSR I Data set ready7 RTS O Request to send8 CTS I Clear to send9 RI I Ring indicatorShell N/A N/A Chassis ground1 — 1314 — 25
