ASR System Integration with Asterisk for SIP or IAX Softphone Clients

This paper provides an insight into the integration of automatic speech recognition with VoIP based Asterisk PBX Server. Softphones are used as VoIP clients which uses SIP and IAX as primary communication protocols to connect to Asterisk PBX Server. A tied-state hidden Markov model based automatic speech recognizer for digits recognition is designed with the help of HTK Toolkit which is integrated with Asterisk PBX server. This paper gives a brief description of the Asterisk PBX Server and system architecture and finally the configuration, integration and implementation of ASR system with Asterisk PBX Server.