Silence Suppression means that when the gateway detects that audio is under a certain threshold on the call, in an effort to save bandwidth, it will stop sending RTP on the link. On the Help menu, click About Microsoft Lync. Microsoft Lync Basic 2013 gives you instant messaging (IM), audio and video calls, online meetings, availability (presence) information, and sharing capabilities all from one, easy-to-use program. Note To determine the version of Lync 2013, follow these steps: In Lync 2013, click the Options button.
Ensure that you turn off Silence Suppression (Voice Activity Detection) on all hops. This article describes update 2817678 for Microsoft Lync 2013 that was released on November 12, 2013.However, if there is a fax setting that allows you to choose G.711 (passthrough), then it can often be a built in function of this setting. This functionality does not usually have explicit settings in a VoIP gateway. This trade off works because fax was built to handle fixed latency caused in long distance PSTN calling scenarios back in the good old days of TDM voice networks. What this does is reduce the chance of Jitter affecting the media stream, by increasing the overall end to end latency on the call. So some gateways will actively try and reduce the amount of jitter by increasing the Jitter Buffers (perhaps to 100ms) for calls that they detect as being fax calls. Faxes don’t like jitter that is caused from variable delays in packetised voice networks.