THOMSON SpeedTouch 716, Руководство пользователя

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Chapter 6
Voice over IP
E-DOC-CTC-20041126-0014 v3.0
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6 Voice over IP
Traditional telephony
For many years, most of the telephony was made on the old Public Switched
Telephone Network (PSTN) and, over time, telephone service providers have
enhanced their services by providing Custom Local Area Signalling Service
(CLASS) features to the customers. Those CLASS features permit subscribers of the
features to tailor their telephone service according to individual needs (e.g.: call
screening, call logging…).
New needs
Rapidly, it appeared that a customised version of the CLASS features is required in
medium-to-large sized business, in order to facilitate business and group
communications. The so-called Private Branch eXchange (PBX) was born!
Voice over IP
Today, Internet telephony, defined as the transport of telephone calls over the
Internet, can be used to send packets between two or more parties without
reserving the connection. Furthermore, based on a powerful signalling protocol
such as SIP protocol, Voice over IP (VoIP) communications allow other Internet
applications as Web, e-mail, chat, presence and instant messaging to be blended
with voice to provide entirely new classes of services and features not available
with circuit-switched telephony.
VoIP popularity
Despite Quality of Service (QoS) issues on the public Internet network and the quick
erosion of cost differentials between PSTN- based telephony and IP-based
telephony, Voice over IP communications are more and more popular.
Consequently, they are pushed by a number of the industry's leading providers,
including Microsoft®, AOL and Yahoo!
The SpeedTouch™ VoIP
solution
Using the SpeedTouch™ you can access VoIP networks using traditional phones.
Depending on the SpeedTouch™ variant you can make your VoIP phone call using:
Session Initiation Protocol
Media Gateway Control Protocol