Pirelli ARV3515J-A-GP, Руководство пользователя

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V
OICE OVER
IP (V
O
IP)
1-2
Voice over IP (VoIP)
An Introduction
Using Voice over IP (VoIP), instead of making calls over the regular
telephone network, calls are made over computer (IP) networks, either
through your Internet Service Provider’s connection or through your local
network. Calls made to another Internet telephone, anywhere in the world,
are generally free, while calls made to a regular telephone are generally
much cheaper than traditional long distance calls.
The basic steps involved in VoIP include the conversion of an analog voice
signal to digital, the encoding and then compression of the signal into
Internet Protocol (IP) packets. The VoIP Router is equipped with a digital
signal processor (DSP), which segments the voice signal into frames and
stores them in voice packets. Using the industry standard codecs, G.711,
G.723.3 and G.729, these packets are encoded. These IP packets are then
transmitted in accordance with International Telecommunications Union
specification SIP over the Internet to their destination where the process is
reversed.
Advantages of Using VoIP
The main advantage of VoIP the traditional Plain Old Telephone System
(POTS) is the ability to make low-cost calls over the IP network. One of
the greatest benefits is local long distance. By using a virtual phone
number with a different area code, you can keep a phone number in
Washington D.C. even though you live in San Francisco. This way, you
won’t pay expensive toll charges when calling Washington D.C., nor will
your Washington D.C. friends when they call you.
Past Problems
Internet-based telephony has been around for years but, until now, has not
reached the mainstream market. Some of the most common problems are
listed on the next page.