Motherboard with only one Com port?

[Knave]

I got a PC Chips PC100 M571LMR (I know, it's my own fault). I have a serial mouse on Com 1. I installed a pnp PCI modem which got set to Com 4. Testing the modem always gives me one of these two messages, "Port not found" or "Cyrix non-MMX CPU not supported!". I'm running a Cyrix 200MMX CPU.

I suspect this motherboard has only one Com port, but the idea is so strange I don't know how to prove it. PC Chips site doesn't say anything. The manual says it has only one SERIAL port. The bios has nothing about any com ports in any menu. I've tried the modem at all other Com ports with the same results.

Can anyone confirm this is possible? Or if you have something I can try, I'm happy to. I guess I could pick up a bus mouse card, or try and find the (optional) ATX form card which gives me a PS/2 mouse connector.

-Michael

[Alzarius]

You've got 2 com port plugs on the motherboard. They are the small plugs to the left of the... Errr, what is it called? Ugh, ok, they are north of the gold TX heatsink and to the left of the white plug looking thing. Anyway, it seems more likely that there's an incompatibility with your Cyrix chip. Quite frankly, I think that PcChips gets the short end of the stick way too often. I hear more people groaning about their onboard ATA66 controllers not working properly or folks that can't get 2 harddrives on one channel on all of the "good" manufacturers boards(Abit, Asus, etc) I've got a PcChips board and I've had absolutely zero problems with it and not one "Hmm, maybe I plugged this in wrong" problem. However, on the other hand, Cyrix chips, however well meaning in price have way too many incompatibility problems. I could be wrong, but... Maybe there's some sort of Cyris patch like the AMD patch... Dunno.Sorry I couldn't be more help.

[EVGTech]

Try turning off plug an play os in the bios. this can have a positive effect on engaging plug and play modems.

[Knave]

Alzarius:
I located the two connectors you mentioned, right where you said they'd be. But only the right-most one is a serial port, the left one is the parallel port. There is no other serial connector on the board.

You may be right about the CPU thing being a problem, though. I just realized the motherboard's auto configure isn't recognizing the Cyrix as a 200 like it's labelled. It's calling it a 150. When I manually set it to the 200 settings, the system is faster but erratic, occasionally freezing up. I'll look for a patch on the PC Chips site.

EVGTech:
I tried turning off the Plug n' Play bios, but it did nothing different. I'm fairly convinced there is only one Com port on this board. I tried disabling the serial port on the bios (note I said "THE" serial port - there is only one in the bios), and then Com 1 was available for the modem, but wouldn't you know it... those idiotic modem manufacturers don't have a way to switch the Com ports using the keyboard, you HAVE to click on it with a mouse. So I can't try it on Com 1 until I get some sort of bus mouse connection going. Argh.

Thanks for you help, though. Still looking...

-Michael

[Knave]

FIXED.

Alzarius, you win the prize. I popped in an AMD chip, and miraculously the modem started to work. No more error.

And the board was NOT mis-diagnosing the Cyrix chip, I looked at the settings when I pulled the chip off and realized that a Cyrix PR200 is really a 150mhz chip.

Have to go find some motherboard that works with this Cyrix...

-Michael

[Alzarius]

I'm glad that you found the cause of the problem. Cyrix chips really need boards designed specifically for them. I get the impression that Cyrix chips aren't reverse engineered from an Intel chip, but that they are reverse engineered FROM a chip that was reverse engineered. And yes, even with AMD chips, or at least PR rating AMD chips, the Mhz is calculated differently. My other AMD K5 166 actually has a 117mhz core, BUT it performs at the equivalent of a 166 mhz Intel chip. Cyrix chips should run on the same theory. And when they work, they should run just fine. But sometimes a motherboard just doesn't get along with a processor, be it AMD, Cyrix or even Intel. A couple games even despised my AMD chip, or maybe the motherboard. But they run fine on my Celron/PcChips board now.

[Axel]

Knave - Don't waste your time with the Cyrix chip.

If you really need to make sure that the board you get has an intel IO chip set in the 430 range. I had a REALLY!!! bad time trying a cyrix chip with a VIA IO chipset -

But I think you will live a happier life in the short run if you trade the Cyrix chip in towards another AMD or a Celeron.

But then, I could be wrong - You may jog and/or drive a TR7 that you love to work on - http://www.sysopt.com/forum/wink.gif