Com ports and gps

[mshuk1]

Please help, I have just spent over £300 on gps equipment
including software and it wont work. The problem is that
I need find out what resourses are using what com ports.
Is there a way I can find a list of used com ports.
Microsoft do not have very much information on com ports
and I am at a loss. Thanks for any help that comes.

 

[Guest]

There are two physical Com ports on most motherboards.
Com1 and Com2. These are multiplexed to give additional
ports Com3 and Com4. 1 & 3 share an IRQ and 2 & 4
share and IRQ. In each case they have independent addresses.
When a port is used (modem, other), the shared Com Port
cannot be used simultaneously.
**If a device on Com1 is active, Com3 cannot be used.

Most PCI modems have their own dedicated Com port on
the card. Since most motherboards BIOS has Com1 on by
default, the modem will normally use Com2.
For years this was a real-pain to configure and was a big
reason for the advent of Universal Serial Buses.

Please help, I have just spent over £300 on gps equipment
including software and it wont work. The problem is that
I need find out what resourses are using what com ports.
Is there a way I can find a list of used com ports.
Microsoft do not have very much information on com ports
and I am at a loss. Thanks for any help that comes.

 

[Willit]

Com 1 and Com 2 are physical ports and have IRQ assignments
From there the ports are virtual There 256 of them. The
problem is once they are assigned they cannot be deleted,
but they can be un-installed there a trick to do. I had a
laptop that I was having issues with and had gone up to
port 16, from failed installs. The program would not
recognize anything above port 5. When you install
something it is automatically assigned the first open
port, but it goes to the higher # ( if 5,6,7 are open and
8,9 are (in use) it will assign port 10 you install
something, thus the problem.

How I corrected it was to take a USB modem and keep
installing it and go into the device manager and change it
to a port that showed (in Use) that I knew was not, then
when that port is accepted go back in and uninstall it.
Keep doing it over and over till you get them all out.

 

[JasonA]

The PCI cards (modems) I've used are either COM 3, 4 or 5 because COM2 is
already used as you stated.