View Full Version : COM port identification

09-08-2009, 06:17 PM
Vista. I have HotSync installed for my Treo which normally uses COM4 to communicate with the phone via Bluetooth.

Something has disturbed this setting recently and now whenever I boot up, some device or program has already reserved this port so HotSync can't use it.

How do I identify the offending program or device (so I potentially change the setting for that program/device)?

09-08-2009, 06:54 PM
You should be able to see in device manager.


09-08-2009, 09:36 PM
Blam - that MSC doesn't exist on my machine.

But if I open Device Manager from the Control Panel, I don't specifically see a list of ports and the applications/devices that are using them...

09-08-2009, 09:38 PM
Sorry. Should be devmgmt.msc

If you expand "Ports" you should be able to the device with the COM port used next to it.

09-08-2009, 09:56 PM
Cheers - I don't have a "Ports" item in the list - is it known as something else?

Can't see it in any of the alternate views either...

09-08-2009, 10:07 PM
Thats weird. Must be a W7 feature or something, as I have it...


Hidden Possibly?

From an elevated command prompt, type set
devmgr_show_nonpresent_devices=1, press enter, then type start
devmgmt.msc and press enter.

Then show hidden devices under the View menu


Speedy Gonzales
09-08-2009, 10:18 PM
Right mouse on the top entry in device manager / scan for hardware changes. Sounds like the BT either isnt working or enabled

09-08-2009, 10:50 PM
I think you're right Speedy - I think there's something screwy with the Bluetooth.

IIRC I had to set up a Virtual COM port when I first got the machine just so I could use HotSync...

Recently installed a Bluetooth headset (Avantalk) and I think things went west from that point (had problems connecting with the headset and people couldn't hear me through the mic). I have removed the Avantalk device, but it hasn't come right...

09-08-2009, 10:52 PM
Blam - when I Unhide, all I get in addition to the normal list is a list on Non Plug and Play devices

09-08-2009, 10:53 PM
BTW - Bluetooth is working - I can connect to the phone OK, I just can't use COM4 to sync...

Speedy Gonzales
09-08-2009, 10:55 PM
What if you double click on the BT icon in control panel?

09-08-2009, 11:07 PM
Phone shows up as an icon, as expected.