User Configuration\Administrative Templates\Windows Components\NetMeeting\Audio&Video
Disables full duplex mode audio. Users will not be able to listen to incoming audio while speaking into the microphone. Older audio hardware does not perform well when in full duplex mode.
Note
The NetMeeting folder containing this policy is created by the Conf.adm administrative template. Conf.adm is included in Windows 2000, but does not load in Group Policy automatically. To display the NetMeeting folder, add the Conf.adm administrative template to Group Policy.