Serial Interface - NEC POWERMATE PROFESSIONAL 9000 Service Manual

Parallel interface signals are output through the system board's 25-pin, D-subconnector.
The connector is located at the rear of the system unit. Pin locations for the parallel
interface connector are given in Appendix A.

Serial Interface

The system has two 16C550 UART compatible serial ports (COM1 and COM2) integrated
on the I/O controller. The serial ports support the standard RS-232C interface. The buffered
high-speed serial ports support transfer rates up to 115.2 KB. These ports allow the
installation of high-speed serial devices for faster data transfer rates.
Sets of I/O addresses and interrupt levels for the two channels are given in Table 1-11 and
Table 1-12. (Note that COM2 is disabled by default.) The interrupt levels are selectable via
the BIOS Setup utility and include IRQ3, IRQ4, IRQ10, and IRQ11. Software-selectable
base addresses are 3F8h, 2F8h, 3E8h, and 2E8h. If serial ports are reconfigured to share an
interrupt, verify that the software and hardware added by users can share interrupts without
problems.
Table 1-11 Serial Port 1 Addresses and Interrupts
Starting I/O Address
3F8
2F8
3E8
2E8
3F8
2F8
3E8
2E8
NOTE: Any interrupts used for the built-in
parallel port are not available for ISA parallel
ports.
NOTE: Any interrupts used for the built-in
serial ports are not available for ISA parallel
ports.
If serial ports share an interrupt, verify that
hardware and software added to the system can
share these interrupts without problems.
Interrupt Level
IRQ04
IRQ03
IRQ04
IRQ03
IRQ03
IRQ04
IRQ03
IRQ04
Technical Information
Port
COM1
COM2
COM3
COM4
COM1
COM2
COM3
COM4
1-25