Asterisk is modular and has so many incredible built-in applications. Modern day call centers require a lot of functionality and, Asterisk provides a contact center platform that is truly versatile, at tremendous cost savings. Live listening in Asterisk is an exciting feature for call center managers. Live listening is not new but Asterisk makes it much more accessible with its chan_spy. G729 is a popular codec (you can purchase G729 license from Digium) which reduces bandwidth consumption to around 45 Kbps per channel. When bandwidth costs are at a premium G729 can provide a 50% savings. Agent phones using G729 can minimize transcoding and reduce system load on Asterisk. Eyebeam, the licensed full featured version of X-lite, is a popular soft-phone with inbuilt G729 codec.
Indosoft call center software Q-Suite runs on Asterisk and we come across a variety of infrastructure variations in our contact center technology deployments. In one such installations which uses G729 for all its outgoing calls, the call center supervisor complained about calls getting disrupted every time they use snoop to perform live listening. We set up a test rig and tried to snoop into a SIP channel with Eyebeam G729 without realizing that the silence suppression was turned on. Many of the applications within Asterisk do not send packets unless they are receiving packets and Asterisk does not support silence suppression. Of course, this is bound to cause issues if the Eyebeam setting allowed silent suppression. Agent will stop hearing the other end when they are silent and listening. But the most interesting aspect is the way this issue gets reported by call center staff as ‘calls getting dropped or cut-off’. It is important to make sure that the setting for silence suppression is left checked as shown in the screen-shot below. A similar issue with the default setting of call inactivity results in X-Lite dropping the the connection .