@Override
        protected void openInt() throws IOException {
            Log.d(TAG, "interfaces:");
            for (int i = 0; i < mDevice.getInterfaceCount(); i++) {
                Log.d(TAG, mDevice.getInterface(i).toString());
            }
            if (mPortNumber == -1) {
                Log.d(TAG,"device might be castrated ACM device, trying single interface logic");
                openSingleInterface();
            } else {
                Log.d(TAG,"trying default interface logic");
                openInterface();
            }
        }
USB CDC/ACM serial driver implementation.

@author mike wakerly (opensource@hoho.com)
@see <a
     href="http://www.usb.org/developers/devclass_docs/usbcdc11.pdf">Universal
     Serial Bus Class Definitions for Communication Devices, v1.1</a>
usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/CdcAcmSerialDriver.java