Hi,

What do you mean by 'tries to connect'? The port is valid it should open OK whether or not a device is connected. AFAIK SerialPort.Open() throws an exception if the specified port is not valid.
Regards,
Viv

>I have a windows app that connects to devices via a com port. (Actually I use a serial emulator but it shows up as com 5). If I don't have the device plugged in or turned on when the application starts and tries to connect the application just appears to hang. Is there a way to test if the com port is a valid port before attempting to connect?
>Thanks
>Tim