SIPSpeaker is a system that provides answering machine service. When the system receives a SIP call, it will establish a new session with user client and send voice data to the user. The user can configure a customized message using a web interface.
The administrator of the system can configure the interface and port number for the web interface; he/she can also configure SIP service interface, port number as well as user name, either using a configuration file or command line arguments.
The system supports multiple session to be communicated at the same time. It uses SIP to manage sessions, and SDP as the handshake protocol to reach an agreement on media format transfered on wire.
JMF is used to support audio playback. And FreeTTS is used to convert message from text to audio format.