Cause:
The NetBotz 500 has the ability to record audio as well as video. The audio recording capability can be disabled via software or hardware.
Resolution:
To disable via software, simple uncheck the ""Record Audio"" check box on under the Camera Pod Capture Settings under Configuration on the Advanced View.
to disable via hardware, insert the dummy plug in the microphone jack on the top of the Camera Pod. Each Camera Pod comes with a dummy plug already installed in this jack. Note that the dummy plug is installed in all Camera Pod 120's by default