I have had a trixbox system at our work for about two years. One of the main issues I have had in the past was getting DTMF working with Grandstream GXP-2000 and Budget 200 extensions. We would like to buy nicer extensions but, the economy will not allow it right now. So, two questions: 1. Does anyone have DTMF working with Grandstream extensions and Elastix? 2. What extension manufacturer do "most" users find the simplest to use?