USB Port searching

[slaphead109]

I'm writing user software which configures the firmware for an electronic device.
It computer is linked to the device via USB.

How do you find which number port to write for?

I can set up a search to find used ports, but if the user has a device using port 4 for example, how can I check it is a USB device?

I am using VB6.

Thanks guys

[namrekka]

Opens that driver a virtual comm port? Then try to open in VB via MSCOMM ports 1 to 16. React on the error codes.

[slaphead109]

MSCOMM was a good start, thanks.

I get error code 8002 - invalid port number if the port doesn't exist, which is great.

If there are 2 ports that are being used, how can I tell which is the virtual USB port please?

[namrekka]

Sometimes 2 ports are used. However 1 port you will use for communication. With MSCOMM its a little problem to get the descriptions. (With API's you can get descriptions but these descriptions are sometimes not reliable).
What I normally do is just try wich one is the good one and store that port for next session. With BlueTooth you must build in a delay for testing if the port is open or not. Sometimes even 2 sec!