Hello Matthew, > You can poll, or you can use > KSPROPERTY_RTAUDIO_BUFFER_WITH_NOTIFICATION. See > http://msdn.microsoft.com/en-us/windows/hardware/gg463060 for > details. Thank you, I had older version of WaveRTPort.doc from 2006, it did not mention this property. Are event notifications supported by all 6.x systems or they may not be supported in earliest Vista releases? Regards, Eugene ****************** WDMAUDIODEV addresses: Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx Subscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe Unsubscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx URL to WDMAUDIODEV page: http://www.wdmaudiodev.com/