Integrating Internet with PSTN networks for voice services

The potential of Internet telephony circumventing long distance rates is ce rtainly appealing as one can talk to someone on the other side of the world for as long as desired at no more than the cost of the local Internet acce ss and connectivity charges. This paper discusses an Internet Telephony Gat eway that allows the delivery of voice services through the Internet to con ventional telephones on the Public Switched Telephone Network (PSTN). The g ateway comprises a hardware interface card, and two software components for session and audio management. The hardware interface interacts with the tr unk line to obtain audio data, answer, initiate and terminate a call. Addit ionally, it converts audio signal into a digital form suitable for transmis sion over the Internet. The session and audio management interface with the Internet for connection set-up, monitoring of the quality of services, neg otiation of session parameters and audio communication.