Interface between Internet and telephone network:
• DSL (digital Subscriber Line) are used by the telecom companies to provide Internet access their users.
• The companies that provide wired phone access will also provide data services to their customers.
• This ensures that the Internet networks have interface to the telecom networks.
Process involved in voice call passing through Internet and telephone network:
• Skype uses this interface to make a phone call from the PC (personal computer).
• When a Skype user makes a phone call from his PC, it passes through the internet and reaches the interface of both the networks. Then it enters into the telecom network and reaches the specified telephone number.
• A proprietary protocol VOIP (voice over internet protocol) is used by Skype for all its communications. It is an internet telephony network based protocol.
• Skype protocol was the first peer-to-peer IP telephone network protocol.
Therefore, Skype uses its proprietary protocol and the interface between the internet and telephone networks to make a voice call from a PC.