Com Port Issue after install of Windows 95

[LWerner]

Hi everyone,

I had an old windows 3.1 machine on which I installed Windows95b. This was not an upgrade.

I need to access both COM1 and COM2 for an engineering voltage test equipment. However, the com ports are not responding.

I hooked up an external modem to these ports and can't get any communication going.

Could the install of windows95 disable these ports, even though there are no conflicts when I look in >properties > device > com ports ?

T:confused:

And if so, how do I get these back?

Thanks,

Laura

[jtdoom]

hi

serial mouse normally used com1 irq 4
then one had com2 irq3
com3 irq4
com4 irq3

you may have to look into BIOS.
commports can be disabled in BIOS.

the most puzzling case I encountered was when the ribbons was connected to wrong header on mobo.
thus, mouse was actually on comm two, but because of a software peculiarity, one thought it was on com 1
Everything looked peachy.
Until the time the guy added a modem, and all hell broke lose
that was when I had to look, and I really scratched my head then (jeesh, this was long time ago... I still had hair)

anyway, the modem would not work on comm 2, not on com 3 and not on com4, and also not on com1
the mouse started acting up too...

I remember I used MSD, and that I looked in BIOS.
and much more scratching happend. (maybe that was when I lost my hair)
Anyway, I eventually looked at the connections INSIDE the machine, and BINGO.

[LWerner]

Hi jt

Well.....this PC is an oldie but still goodie. It's a dell P90 and I'm not sure whether the ports ever worked.

We just needed an older machine that I could load Win 95 onto and then use basically as a "test" machine that runs a program that uses the com ports.

Somewhere back in my memory, I think I remember something about the com ports being disabled during the install of Windows 95. And, I think there was a fix....but can't remember what.

Anyway, I checked the intenal cable connections and they both look fine. I was also looking for the jumpers. They're not on the modem itself (Practical Peripherals 14400) and I don't see any near the cable connections on the mobo. I'm just trying to get this modem working on one of the ports to verify that the COM ports themselves weren't the issue we're having with our engineerning test equipment.

I've tried connecting the modem to both COM1 and COM2 and and there is no communication with either.

If you think of anything else I can try, please send it along.

Thanks again,

Laura

PS: Bios is set to AUTO detection and in the DEVICE MANAGER in windows, it shows that I have 4 com ports and that "they're working properly". Ho - hum

[Alfons]

If the Serial Port connecters are on the MB, then the BIOS will have the Setup capability to enable or disable COM1 & COM2 as well as select the address & IRQ combination for each. Your Parallel Port setup is on the same BIOS page. Some of the early pentium MB's had an I/O adapter where the IDE & Floppy were disabled by on-the-board jumpers and the Serial & Parallel ports were made active - the MB had the on-board IDE & Floppy (The old PC Chips boards come to mind).

If you've never used these on W3.1, they may just be turned off in the BIOS. If they actually don't work, you can motor down to your local computer "salvage" shop & get a used ISA I/O card - they're usually very reliable & the jumper settings are also usually very easy to place.

Did you check in the Device Manager to see if Windows could see them? Do you know the MB make & model? If yes, you could get any updated drivers for it.

[LWerner]

Hi Alfons,

If the Serial Port connecters are on the MB, then the BIOS will have the Setup capability to enable or disable COM1 & COM2 as well as select the address & IRQ combination for each.

Yes, ports are located on the MB, and the setting in the BIOS is set to AUTO.

Did you check in the Device Manager to see if Windows could see them?

Device Manager shows COM1 thru COM4 and all are reported to be working properly and have no conflicts. Just want to mention that there is nothing fancy about this machine. It was a Win3.1 machine and I just deleted the C:\windows directory and installed Windows 95b as a new install. There is nothing extra added. Not even Internet Explorer. No other programs other than whatever comes along with Windows95b.

The com port connections are on the MB and I don't see any jumpers that pertain to them. I have a schematic and system board layout for the jumpers, and I don't see anything that pertains to the com ports. This puter is a Dell Dimension P90 and probably 6-7 years old. Definitely out of service as far as Dell is concerned.

I've hooked an external modem to the port and tried setting up the dial-up and it's not finding the modem or port. My guess is that somehow the install of windows 95 has something to do with this.

There is a report put out by Intel for "Intel Mother boards Using 82371SB PIIX3 or 82371AB PIIX4 Component that says: Some versions of Microsoft Windows 95 may not recognize the IDE controller in Intell motherboards using the above components. This can cause the BIOS to disable the secondardy IDE channel, resulting in IDE devices (such as CD-ROM drives) not being detected or disappearing after the system is rebooted.

This CD-ROM thing has happened to me before on other machines that I 've had to upgrade. There is a utility that I downloaded from Intel that fixes the CD-ROM. I was just wondering if this same program would address the COM port issue.

I can't determine what kind of MB I have, so I'm not sure if I should run the program or not.

Anyway, I guess I'm rambling here. If I purchase an ISA I/o card, do I need to change the settings in the BIOS for the serial ports to "DISABLED" rather than" AUTO"? Or do I just "unplug" the ports that are on the MB?

Thanks again for the input.
Laura

[jtdoom]

Hi

maybe you have a non plug and play modem, and win95 P&P was shaky at best.

I assume you tried options, control panel, new hardware?

but, it is kinda weird.
based on my experiences with them, external modems are the easier ones to install.

[LWerner]

Hi Jtdoom

Yeah I agree with the install of "external" modems. Windows just didn't know it was there. It went through the search of all 4 COM ports and couldn't find it. That's why I belive it's a MB issue. Also, I'm not sure these ports ever worked.

So, what I did was take the HD from this machine and put it in the computer whose HD crashed. The ports were working on that one and now all the Engineers are :D again! and me too :D :D :D

Sorry I can resolve this issue here. If I come across any other info that will fix the MB, I'll try to post and pass it along.

Thank you, everyone for the suggestions.

Laura

[Alfons]

Just to answer your last questions even though you don't appear to need the answers just now.

MB's wit on-board Serial Ports have no jumpers for their setup, it's all done in the BIOS setup.

If you add an I/O card to give you the COM 1 & 2 functionality, then you need to disable the on-board devices (BIOS setup).

You can always go to the Chipset manufacturer's website & look at their archived drivers. Find the latest for the chipset on the MB for your OS & give that a try.

I've had more luck setting the COM 1 & 2 to specific settings instead of AUTO which was somewhat flaky in earlier days.

I have an old Tomato board that reports working COM 1 & 2 Ports but in reality they don't work so I use an I/O adapter for it - works great - just need to remember to disable all features that you're not using, like IDE & Floppy on the I/O board & Serial & Parallel on the MB. These devices have no way of testing the input side so you need to plug something in to do a full test - no full loopback.

[LWerner]

Thanks, Alfons.

Will print this for my file. I know if I don't, by the time I get around to this one again, I'll forget what we just talked about and I'll have to start all over. :p

Thanks for all the assistance.

Laura

[jtdoom]

I just thought of something else

com 1, irq 4, adress 3F8
com 2, irq 3, adress 2F8

the adress may have been changed in BIOS, so it is no longer at default.

also, some external modems, and many old internals had jumpers or dipswitches to set comport, irq and adress.
If the adress is used by another device, it won't work.
(no wonder we talked of plug and pray)