
designation.
Both the new and the remapped COM ports share the same IRQ setting, as follows:
COM1, COM3: IRQ4 (shared setting)
COM2, COM4: IRQ3 (shared setting)
These COM ports have the following I/O address settings:
COM1: 3F8h
COM2: 2F8h
COM3: 3E8h
COM4: 2E8h
For example, if you add an internal modem card with a port configured as COM1, the computer then see s logical COM1 as the address on the modem card. It automatically remaps the
Before adding a card that remaps the COM ports, check the documentation that accompanied your software to make sure that the software can be mapped to the new COM port designation.
To avoid autoconfiguration, you may be able to reset the expansion card's jumpers or switches so that its port designation changes to the next available COM number, leaving the designation for the
The
For general information on how your operating system handles serial and parallel ports as well as for more detailed command procedures, see your operating system documentation.
Serial Port Connectors
If you reconfigure your hardware, you may need pin number and signal information for the serial port connectors. Figure
Figure B-3. Pin Numbers for the Serial Port Connectors
Table B-3. Pin Assignments for the Serial Port Connectors
Pin | Signal | I/O | Definition |
1 | DCD | I | Data carrier detect |
2 | SIN | I | Serial input |
3 | SOUT | O | Serial output |