I'm not sure, I believe we've tried it with a semi-busy node and had the same issue. Curiously, he can make a call across a trunk to my Asterisk box, and we can both mute our phones and it won't drop after an hour. I'd never heard of VAD, but will look into it. Thanks for the info Benjamin! 73, Kyle K0KN --- Original Message --- Activity disconnect? Maybe the phone has VAD turned on, and if there is not RX audio traffic, it thinks the line is hung and drops... Does the Polycom hang up when there is traffic? just guessing, haha ~Benjamin, KB9LFZ