If you're having issues with the microphone on your headset, try the following:

• Check that the microphone isn't set to mute either on the headset or in the application where you're using it.
• Make sure you have the H600 headset selected as the audio input/recording device (see your computer or device's documentation for help).
• Ensure the application you're using is configured to use the headset as its audio input/recording device (see the application's documentation for help).
• Make sure the receiver is connected to a USB port that isn't behind any large objects (ex. a desk or desktop PC).
• Connect the headset to a USB port with the charging cable — it may not have enough battery power.