View Full Version : Comm ports and modems

14-05-2003, 09:41 AM
Hmm... Looks like I did not explain things clearly last time :-)

Tried to install a new Dynalink 1456VQE external modem onto an Athlon 1.2 Ghz ME machine with 20 gig HDD and 512 ram.

Followed the excellent instructions to the letter but when it came to the modem detecting the com port (I selected com2), the modem cycled through comm1 to comm 9 and ended up with a message that it could not detect a com port.

OK, to test things out I fitted the modem to another computer and it installed perfectly first time, in fact I am using the modem for this.

Looking at Start/Control Panel/System/Ports on the faulty computer , it reports evenything is fine with both cvom 1 and 2, no errors, no conflicts and the message that the item is working correctly.

My question, does this signify a stuffed motherboard (everything else including LTP1 works just fine). The second question, are comm ports software controlled, to the extent that the port could be deleted and then re-installed and hopefully cure the problem in the process?

Perhaps even, there is something else that is preventing the modem detecting a com port

Any thoughts please.

Graham L
14-05-2003, 01:16 PM
The COM1 and COM2 ports are normally part of the motherboard hardware. They can be disabled in the BIOS setup, which might be what is wrong with your COM2.

The Windows hardware Manager (or your modern equivalent) doesn't necessarily know anything. :D

The modem doesn't "detect" a port. It is plugged into the port, and the modem is detected by the computer, if everything is OK.

I would check the BIOS to make sure the ports are enabled.

14-05-2003, 06:01 PM
Thanks for the reply Graham L.

I went into BIOS and both com1 and com2 are set to Auto, however I can manually set them to 2E8/IRQ3, 3E8/IRQ4, 2F8/IRQ3 or 3F8/IRQ4.

Obviously com1 and com2 should not be set to the same values. but is one of the four setting listed considered "reccomended/ normal etc"

As a last resort my WinME comes with a restore disk, where the most sever option is to wipe the disk clean and re-install ME, but in your opinion is that likely to fix the problem, (2779 posts no less = quite experienced ) . :-)

Anyway, at the worst, perhaps there is nothing to loose. Assuming nothing fixes the problem and just for my education, would you consider the failure to be hardware or sortware? Again thanks.

14-05-2003, 09:23 PM
Try starting up hyper-terminal (under accessories). When asked, set it up for com 2 which you have your modem plugged into. Then type in and enter AT&V This should cause a lot of data to appear on your screen if you can talk to your modem. If not sure, try it on the working PC first.

Graham L
15-05-2003, 02:15 PM
The standard I/O port addresses and IRQs are:
COM1 3F8 4
COM2 2F8 3
COM3 3E8 4 (the IRQ doesn't "share" successfully with COM1
COM4 2E8 3 (ditto with COM2)

(while I'm here, here are most of the other "legacy" addresses and IRQs.
PCI plug and play can allocate other addresses (expecially 4 digit hex addresses, and share (more or less successfully, IRQs).

LPTs can appear at 378, 278, or sometimes 3BC; IRQs 5 or 7

Keyboard uses IRQ 1
the PS/2 mouse port uses IRQ 12
floppy drive controller uses 3F0, IRQ 6
IDE primary uses 1F0 , IRQ 14
IDE secondary uses 170, IRQ 7

16-05-2003, 08:06 PM
Graham L and Pheonix

Thanks for the advise Guys, Pheonix spot on. my com2 is faulty.

Still don't know if it is software or hardware related, but whatever. it don't do nothing.

Probably means another m/board though, as I have other devices that need/ insist on a port of their own. Oh well, at least the modem now goes. Again thanks.

Graham L
17-05-2003, 01:58 PM
You can buy PCI (and sometimes ISA :D) cards with serial ports. Cheaper than a motherboard.

17-05-2003, 02:28 PM
Great, actually thought I had heard of a PCI based port card.

It will be the way to go as other than a faulty com2, everything else related to the motherboard works just fine and I have a couple of PCI slots empty too. No ISA :-)

Thanks Grahame L