Virtual COM. Detect event

[Gimpsi]

Hi.

I have a Virtual COM port that allow me to emulate an RS-232 on a USB port. This means that when i insert an appropriate external USB peripheral, a new COM port in my system appears.

I wold like to capture the operation system event generated when the exeternal peripheral is removed (and the COM port disappears). Otherwise i must do a polling (or wait for a write error) to know if the exeternal peripheral is still present, but i wouldn't....

Please help me!

[Nick_]

Hi,
you could use windows API to obtain this information, in particular you could pass trough the Microsoft SysInfo Control ActiveX.
This ActiveX can notify your program device add/remove events.

Take a look at these MSDN links for information

DeviceArrival Event
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/sysinf98/html/scevtDeviceArrival.asp

DeviceRemoveComplete Event
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/sysinf98/html/scevtDeviceRemoveComplete.asp

Looking for "ActiveX" in NI Example finder you'll find examples on registering activeX events.

With this been said, it could be a lot easier to create a subVI that calls "VISA Find Resource.vi" and look for added-deleted COM resources!

Ciao.

NicolaC
National Instruments