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1-14 Technical Information
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 and the IR
interface (see Table 1-7). The buffered high-speed serial ports support transfer rates up to
19.2 KB. These ports allow the installation of high-speed serial devices for faster data
transfer rates.
I/O addresses and interrupt levels for the two channels are given in Table 1-7. The interrupt
level is selectable via Setup to either IRQ3 or IRQ4. Software selectable base addresses are
3F8h, 2F8h, 3E8h, and 2E8h.
NOTE:
Any interrupts used for the built-in
serial ports are not available for ISA parallel
ports.
Table 1-7 Serial Port Addressing and Interrupts
Starting I/O Address
Interrupt Level
Port
3F8h
IRQ04
COM1
2F8h
IRQ03
COM2*
3E8h
IRQ04
COM3
2E8h
IRQ03
COM4
* Used for IrDA data transfer
See Section 2, “Setup and Operation,” for information on resetting the port through Setup.
Serial interface specifications include:
Baud rate up to 19.2 KB per second
Word length - 5, 6, 7, or 8 bits
Stop bit - 1, 1.5, or 2 bits
Start bit - 1 bit
Parity bit - 1 bit (odd parity or even parity).
Serial interface signals are output through the system board’s 9-pin, D-subconnector. The
connectors are located at the rear of the system unit. Pin locations for the serial interface
connector are shown in Appendix A.
Summary of Contents for MT-2550-24874C
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