[asterisk-users] Re: How can I improve call quality?

[Jan Gerryt du Toit]

We had similar QoS problems as described but only within meetme rooms. As you
know  the meetme app needs zaptel to be installed, this is because the meetme
app needs a timing device. Now, if one does not have any cards installed on the
box, then one needs to load the ztdummy for the meetme app to work. As its name
suggests this is a zaptel dummy and it provides a software timing device. It
turned out that this software timer is not that great and caused all the QoS
problems. Our problems were solved by plugging in a physical card into the box.
This way the meetme app uses the hardware timing device on the card itself. 

Our setup is still 100% SIP - the card is only used for timing purposes.

Hope this helps.