USB headsets are treated by windows as a seperate sound card. If you are having audio trouble, click the little question mark at top left corner and be sure the correct sound card(s) are selected.
When you talk into the mic while transmitting, the S-Meter should bounce with your voice, peaking about s9 to 10dB over. Adjust the transceiver Mic Gain knob as required.
If your mic is still not working, click Audio Input Mixer and be sure mic is SELECTED and turned up.
Some headsets have a hardware Mic switch embedded in the headset wire.
If you hear a squealing feedback from your speakers, click the Audio Input Mixer and be sure that Microphone is MUTED in here.
IF you still have problems, close CQ100 and open Windows Sound Recorder. If the Windows Sound Recorder can record and play your voice, your sound card is ok. If Windows Sound Recorder has the same problem, then you need to check you hardware wires and sound card and your Windows configuration under Control Panel.
Check in Control Panel that your GSM 6.10 codec has not been turned off or removed. This codec has installed with all versions of windows since Win 95. Someone reported he adjused the priority of GSM 6.10 codec in Windows control panel to solve transmit problem.