we are using our C# application which communicates with wp7607-1 on mangoh-red via WWAN Modem Port. Normally it works well, and so we can execute all the at commands. The issue happens when we remove usb cable. Our application detects the USB disconnection and close the port. The mangoh-board is still powered. Then when we connect the usb cable again, we see on hardware manager that alle ports are listed. But our c# is not able to open the modem port and says the port is busy. It reamins busy all the time even when we reboot the module. We have to stop our application, and then we have access to the modem port.
What is wrong? Driver problem?