Addrlpt Program; The Comtest Program - Brainboxes RS422 Manual

AT & OPTO DUAL RS422/485
The ADDRCOM programs take one parameter, the
hexadecimal port address. The programs can be run from the DOS
command line or from batch files like AUTOEXEC.BAT.
To set COM3 address from the DOS command line enter:-
ADDRCOM3 03E8 <return>
To set COM4 address from the DOS command line enter:-
ADDRCOM4 02E8 <return>
To set the COM port address from within the
AUTOEXEC.BAT file use a text editor to add the following lines
to the file.
ADDRCOM3 03E8
ADDRCOM4 02E8

ADDRLPT Program.

The ADDRLPT programs are used to set the parallel port
address in the BIOS and work in exactly the same manner as
ADDRCOM3.

The COMTEST Program.

The COMTEST program is a comprehensive serial port test
program. It utilises the LOOP BACK self test mode of the serial
port chip. The program is menu driven and allows the user to enter
their own serial port address or choose from a range of predefined
ones.
COMTEST tests the scratch register, an excellent way of
checking the read write path to the serial port chip. Older serial
port cards using the 8250 chip will fail this test.
COMTEST tests the input and output handshake lines and
it also tests the transmitter and receiver at a variety of baud rates
from 115,200 baud to 110 baud.
Any serial port that fails any of the tests should be
considered suspect. Note an interface card may still fail to perform
Serial Utilities and Programming
Chapter 5 Page 57