Program using Com Port 1

[Guest]

When I power my system up, Hyperterminal says that some other application is
using my Com Port 1. I don't have any modems, dialup or serial applications
running. How can I find which application is attached to my Com Port 1?

 

[Shawn Morgan]

It may actually be windows itself using Com1. Another scenario is that
COM1 may not even exist. My notebook has no com ports, but windows insists
they are there and says they're just busy.

Try using a DOS disk (boot disk) and program to connect to COM1 and see if
it works there. If it doesn't, are you sure you have one?

Shawn.

 

[Guest]

I have a Com Port 1 and it is working just fine. I do not need to test it in
DOS, I am sure that it works fine. What I want to know is that if Windows XP
will not give me access to Com Port 1, is there any way to tell in Windows XP
why and what application has Com Port 1 allocated? Surely Windows XP has
deterimined that it thinks that the port is in use. I just need to know who
is using it.

 

[R. McCarty]

Use Everest Home Edition - Run & Expand the Devices category,
then expand Physical Devices. Any COM ports should appear in
the listing.
Download the latest Everest here:
http://www.lavalys.com/products/download.php?pid=1&lang=en&pageid=3

 

[Si Ballenger]

Sometimes windows thinks there is a serial mouse connected.
Probably need to check in device manager. "hot sync" software
often grabs the serial port if that type of software is on your
computer and loads on start up.

 

[Guest]

I loaded the Everest software. It doesn't tell me which application has
allocated the Com Port 1. How can I tell which application is using Com Port
1?

 

[Admiral Q]

Do you have a modem connected to COM1? Normally HyperTerminal is used where
a "telnet" emulation connection is required to another system, either via
telephone or network, telephone being modem, network being a NIC. Either
way, you don't configure the COM1/COM2 unless you are using a direct connect
crossover cable to another computer's COM1/COM2.

--
Star Fleet Admiral Q @ your service!
"Google is your Friend!"
www.google.com

***********************************************

 

[Thomas Lutz]

If there is a device connected to COM1 on your PC that is transmitting
data when Windows boots, Windows will sometimes assume that the device
is a serial mouse and install a serial mouse driver for the COM port
and thereby make the port unavailable to other applications.

There is one simple way to test if this is the problem and that is to
disconnect whatever device is connected to COM1 and reboot.
If you can open COM1 with no device connected to the port then that is
the problem.
The following article on the Microsoft web site describes how to cure
the problem by using a switch in the BOOT.INI file:
http://support.microsoft.com/kb/131976


If you still cannot use the port then some other applciation program
has the port open.
You could use the Task Manager in Windows to see what other programs
are running and perhaps shut them down one by one until you discover
which one has the COM port open.
Do you have Pocket PC or Palm Pilot that you connect to the PC?
ActiveSync and the Palm Desktop software commonly open the COM port
and leave it open.

You may also want to check the BIOS settings on your PC to see if COM1
is enabled or what its settings are.

The last possibility is that you have some other hardware device
installed that is using the IRQ that COM1 is assigned to.
For example, COM1 normally uses IRQ4. If your network adapter is also
configured to use IRQ4, your COM1 port will be effectively disabled
because the network adapter driver will own the IRQ and the COM port
will appear to other programs to be in use.

For more serial I/O tips, tricks and free utilities, visit
www.taltech.com