Try out Ozeki VoIP SIP SDK. You can download and use trial version free of charge.
Here is the link:
http://voip-sip-sdk.com/p_21-downloa...-sdk-voip.html
I would like to mention another page as well. It is useful to get more information on IVR systems:
http://www.voip-sip-sdk.com/p_413-vo...tion-voip.html.
I think it is worth reading those valuable webpages.
Bye
