Uncreative Labs

Joined: 27 Jan 2007 Posts: 274 Location: USA

I'm almost done rebuilding my messed up 386 and the last problem is com3 doesn't work. the mb and the modem work ok and i dont think theres a conflict but I could be wrong.

onboard serial=com1 irq4
modem=com2 irq3
i/o card =com3 irq4

the i/o card is giving me problems.
msd cant find it and i dont know what else i could do to test it.

Joined: 19 Apr 2006 Posts: 261 Location: WisConSin

Why are you trying to use more than 2 COM ports?

Generally there is no point in having a COM Port 1 & 3 on the same machine. Needless to say COM 1 & 3 and COM 2 & 4 generally share the same IRQ and many times won't work at all at the same time, AKA COM 1 & 3 won't play nicely if used at the same time, same for 2 & 4.

If you are very lucky the best you can do is have COM 1 work, then stop it and send data from COM 3 and stop but never at the same time without special multi/io cards. This can almost be workable if one COM port is on a modem and the other shared port is for something intermittant like a data cable to a PDA or camera. But if both ports are to be in use it usually doesn't work.

Now why your com 3 doesn't show up at all is a mystery, unless you have a serial mouse on com 1 and are running the diagnostic then.

You could try disabling COM 1 to see if com 3 works, if it does your machine has the classic problem of not wanting com ports on the same IRQ which is a hard one to fix.

Good Luck

Joined: 27 Jan 2007 Posts: 274 Location: USA

My problem is all fixed now. i can hook a serial mouse up to com3 and the driver can find it. I use com1 for a mouse com2 for a modem and com3 is used for interlnk and intersvr. Thank you for your advice and I usually dont use com 1 and 3 at the same time anyway.

Joined: 03 Feb 2006 Posts: 488 Location: pennsylvanai

as said com 1 & 3 irq4 and 2 & 4 irq3
however i/o cards come in 3 "flavors"
1) no way to turn ports off or on
2) jumpers to do so bit that don't really work
3)i/o cards with jumpers that really work

in a pinch , of there is no sound card i think
irq5 com 2 can ne used. but sound cared are almost always on irq5.

withj newer pc's the com ports are often unused and they can be turned off in the cmos setup.

Posted: Wed Feb 28, 2007 9:51 pm

Yeah it is different now, I allways disable com and lpt any USB ISA cards for XT Wink

Joined: 27 Jan 2007 Posts: 274 Location: USA

ISA USB

There ISA USB cards!

Posted: Thu Mar 01, 2007 9:56 pm

no but there are USB to a virtual ISA though

http://www.arstech.com/item--usb2isa.html