VoipGain was developed in order to help you to perform low-rate voice over Ip calls. It stands as an easy-to-use application that provides quick access to all its tools and setting options. The interface is user-friendly an allows you to easily find your way around the program.
Program is working well in 80% of cases; pricing is very attractive. Main problem is the total lack of user support.
Here is the product site http://phyzios-studio.net/Default.aspx