COM port problem / XP

[javier]

I am using a special interface that connects my diving
computer to one of the serial ports in my PC.
This interface stopped working a few weeks ago (it worked
fine for several months)- I get a message that the
interface is not detected in any of the COM ports. To make
sure that the interface is working, I checked it on a
WinNT4 PC and it works fine, so the problem is not the
interface (or the rs232 cable).

The device manager says all serial ports are working
properly and that there are no conflicts.

Is it possible that one of XP's services is causing this
problem, or some other software running in the background
is blocking the access to the serial ports?
Any clues what I can do, or how I can check what causes
the problem?

Thanks,
Javier

[Chris Kusmierz]

"javier" > wrote in message
...
> I am using a special interface that connects my diving
> computer to one of the serial ports in my PC.
> This interface stopped working a few weeks ago (it worked
> fine for several months)- I get a message that the
> interface is not detected in any of the COM ports. To make
> sure that the interface is working, I checked it on a
> WinNT4 PC and it works fine, so the problem is not the
> interface (or the rs232 cable).
>
> The device manager says all serial ports are working
> properly and that there are no conflicts.
>
> Is it possible that one of XP's services is causing this
> problem, or some other software running in the background
> is blocking the access to the serial ports?
> Any clues what I can do, or how I can check what causes
> the problem?
>
> Thanks,
> Javier

Try using HyperTerminal to open the comm port and see if you can **see** the
data coming in the port, if you find the comm port is in use, check for the
existence of a serial mouse or other serial pointing device in device
manager. If you find one right click it, click properties, and under device
usage choose **disable**

W2K and XP have been known to interpert serial devices as pointing devices
and automatically install the drivers, therefore hijacking the comm port.

HTH
Chris

[Si Ballenger]

On Wed, 17 Sep 2003 01:15:06 -0700, "javier"
> wrote:

>I am using a special interface that connects my diving
>computer to one of the serial ports in my PC.
>This interface stopped working a few weeks ago (it worked
>fine for several months)- I get a message that the
>interface is not detected in any of the COM ports. To make
>sure that the interface is working, I checked it on a
>WinNT4 PC and it works fine, so the problem is not the
>interface (or the rs232 cable).
>
>The device manager says all serial ports are working
>properly and that there are no conflicts.
>
>Is it possible that one of XP's services is causing this
>problem, or some other software running in the background
>is blocking the access to the serial ports?
>Any clues what I can do, or how I can check what causes
>the problem?
>
>Thanks,
>Javier

I've just found out after a bunch of wasted time that for XP to
see an external modem, the modem has to ae attached to the com
port and turned on, then XP rebooted. With your gizmo attached
and turned on, reboot XP and see if it is now recognized.