Silence suppression makes the best use of available bandwidth, such as the connection over which the caller is listening, not speaking. Silence suppression works by sending descriptions of the background noise, rather than the actual noise itself, during gaps in conversation, thereby reducing the number and frequency of voice packets sent on the network. Background noise is very important during a phone call. Without noise the call will feel very unnatural and give a perception of poor quality.  Ensure that silence suppression configuration matches at both ends of the SCN trunk for correct operation and also for improved sound quality.