Abstract
In the Internet telephone System, Users can make a long-distance telephone call using existing analog phone sets directly rather than the computer interface. This thesis describes the design and implementation of the system prototype, which is developed on Pentium Pro 166 machine running Windows NT 4.0 with Dialogic D/41ESC Computer Telephony Interface (CTI) cards.A common aspect of speech transmission through packet-switch networks is the need of considering the missing packet as a result of the network traffic overload. The missing packets and the possible mistracking that result in the quality degradation. We compared three kinds of compensated scheme to compensate the missing packets.The primary purpose of the thesis is to show that the recovery techniques by the features of G.723.1 and a simple jitter control scheme to suit the variation of traffic and keep the speech quality acceptable.In the current implementation, the end-to-end delay is limited to 161.65 million seconds. The experimental results indicate that our system can tolerate 60% traffic load over LAN. If the traffic load is over 60%, the inter-arrival time will be unpredictable, and the loss-rate will grow dramatically. Under this circumstance, we apply a simple real-time compensation scheme as well as a jitter control scheme to fix the damage during decoding.