Technical information

What To Do First Serial Solutions
Once the PC has been booted with the COM3 parameters in the
CONFIG.SYS file we could now use NEWMODE.EXE and
EASYC.EXE with this port.
NEWMODE COM3:9600,N,8,1 <return>
EASYC COM3 <return>
Setting Up For COM4.____________________
In the same way we could add the configuration for a COM4
port using interrupt line IRQ11. The CONFIG.SYS entry
becomes:-
device=c:\newcom.sys /A3,3E8 /I3,10 /H3,4 /A4,2E8 /I4,11 /H4,4
COM1-4 Defaults.________________
Serial Solutions assumes that COM1 is at 3F8hex using interrupt
4 and that COM2 is at 2F8 hex using interrupt 3. This is the
industry standard. COM3 is usually at 03E8hex and COM4 at
02E8hex.
Modern PCs can usually find the COM3 and COM4 port
addresses and indeed often display them on screen as the PC
boots up. In these cases, Serial Solutions will get the COM3 and
COM4 addresses directly from the PC’s BIOS table and
therefore the /A3 and /A4 parameters can be omitted.
However, since there is no fixed standard for the
interrupts for COM3 and COM4 ports the /I3 and /I4
parameters must always be passed on the NEWCOM.SYS
line in the CONFIG.SYS file.
COM5 And Above._________________
There are no industry standards for COM5 and above. This
means that there is no agreed i/o addresses or interrupts for
COM5 or greater. As a result Serial Solutions cannot determine
from the PC’s BIOS, nor can it assume, how these serial ports
have been configured in the PC. Therefor the addresses, interrupt
line and handshake type for COM5 and above have to be made
Chapter 1 Page 5