Hi, > The multi-port cards I've used in the past have been ISA. I did have > to modify some of them to share interrupts, but that's always worked > OK. Of course these won't fit in most recent computers. Multi-port > PCI cards I've seen handle interrupt and I/O addressing differently > from the way the ISA cards did it. I/O addresses are no problem, any > address is configurable in the software, but despite claims to be able > to use IRQ3 and IRQ4 in the sales literature none of the PCI cards > that I've tried so far appears to be able to use either.
some warnings first: my (extensive) experience with COMx is ~23 years old, so I may be wrong. expect COM1234 to be located on 0x3f8,2f8,3e8,2e8 (as indicated at 0x40:10) expect interrupts 3,4,3,4 https://de.wikipedia.org/wiki/Interrupt says 3 COM 2, 4, 6, 8 (EIA-232/RS-232) 4 COM 1, 3, 5, 7 for the obvious question where COM5678 have their ports, you have to consult PCISCAN utilities, or the wider internet... only if that doesn't work, dig deeper. > My software > expects that only those will be used for serial comms (if you think > that means the software is silly, I'd blushingly have to agree). even in hindsight, I *think* even today only 3 and 4 are used. it might be useful to install linux, windows, or whatever on a machine with such a multi-port adapter and use settings->devices->COM5->properties to investigate this. > At some point I'd like to modify the software to handle more recent > hardware but it's a long time since I did all that and I've almost > forgotten how it all hangs together. +1 tom _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
