Last I looked at Sphinx, it had issues with 8khz audio which resulted in really poor performance. There s not a lot of people talking about successful deployments of Sphinx in real environments, but you might be able to get it to work with some trailblazing effort. See here for more info:

http://www.voip-info.org/wiki-Sphinx

The closest thing to open-source that really works is using LumenVox with Asterisk. Asterisk is the open-source PBX that you can use to integrate with a VoIP service or gateway, or even the PSTN. LumenVox is a commercial speech engine that integrates with Asterisk:

http://www.asterisk.org
http://www.lumenvox.com
http://www.lumenvox.com/partners/digium/Asterisk.aspx

There s lots of people successfully using LumenVox with Asterisk.

您可以尝试将Sphinx与星号：

• http://www.syednetworks.com/asterisk-integration-with-sphinx-voice-recognition-system
• http://www.voip-info.org/wiki/view/Sphinx