The port cannot be opened, or is being used by another application

what are the various possible way of communication with OP27. how to check transfer setting as unable to enter transfer settings??

1. Power OFF.
2. Keep pressed ESC+Aroow UP
3. Power ON.
4. System switches to Download Mode. (you will see a message).
5. Release the buttons.

I am using Siemens PLC (S7-200 CPU .Micro Win V4.0 SP 8, and for communication am using ppi adapter.the plc can not communicate with the computer .it gives me
"The port cannot be opened, or is being used by by another application.

Shutdown all applicatons, look in your startup folder for applications that might use the same (pc) port.
Restart PC.
Start microwin and select right pc/pg interface.
Put CPU in stop mode and try again.

Author: Ashu