@bobnoordam

How can I verify that my local COM ports are redirected in an RDP session ?

A: Start a command window and type the following command at the prompt:

change port /query

The output will look something like this:

AUX = \DosDevices\COM1
COM1 = \Device\RdpDrPort\;COM1:15\tsclient\COM1
COM2 = \Device\RdpDrPort\;COM2:15\tsclient\COM2
COM3 = \Device\RdpDrPort\;COM3:15\tsclient\COM3
LPT1 = \Device\RdpDrPort\;LPT1:15\tsclient\LPT1
PRN = \DosDevices\LPT1

From the above, you can see that COM1-3 and LPT1 are redirected. The number 15 is the session id, so that will change depending on the current session id. If they are not redirected, the output will look something like this:

AUX = \DosDevices\COM1
COM1 = \Device\Serial0
COM2 = \Device\Seri