Serial Interface; Indicator Panel; Serial Port Addressing And Interrupts - NEC POWERMATE 4100M Service Manual

1-16 Technical Information

Serial Interface

The system has two standard serial ports (COM1 and COM2). The serial ports support the
standard RS-232C interface (16550 compatible). I/O addresses and interrupt levels for the
two channels are given in Table Section 1-8. The interrupt is selectable via Setup to either
IRQ3 or IRQ4. Software selectable base addresses are 3F8h, 2F8h, 3E8h, and 2E8h. Serial
interface signals are output through the system board's 9-pin, D-subconnector. The con-
nectors are located at the rear of the system unit. Pin locations for the serial interface con-
nector are shown in Appendix A
Table Section 1-8 Serial Port Addressing and Interrupts
Starting I/O Address
3F8
2F8*
3E8
2E8
*Default for serial port
Serial interface specifications include:
n
Baud rate up to 19.2 KB per second
n
Word length - 5, 6, 7, or 8 bits
n
Stop bit - 1, 1.5, or 2 bits
n
Start bit - 1 bit
n
Parity bit - 1 bit (odd parity or even parity).

Indicator Panel

The indicator panel is attached to the front panel and contains the power lamp, hard disk
drive busy lamp, and reset button. The indicator panel attaches to the system board using
connector P5 (reset connector), P7 (hard disk drive busy lamp connector), and P15 (power
lamp connector).
NOTE: Any interrupts used for the built-in serial
ports are not available for ISA parallel ports.
Interrupt Level
IRQ04
IRQ03
IRQ04
IRQ03
Port
COM1
COM2
COM3
COM4