Voice over Internet Protocol
An overview of how VoIP works A typical analog
telephone adapter for connecting an ordinary
phone to a VoIP network.
A Voice over Internet Protocol (VoIP) is a protocol
optimized for transmission of voice through
the Internet or other packet switched networks.
VoIP is often used abstractly to refer to the
actual transmission of voice (rather than the
protocol implementing it). VoIP is also known
as IP Telephony, Internet telephony, Broadband
telephony, Broadband Phone and Voice over Broadband.
"VoIP" is pronounced voip.
Companies providing VoIP service are commonly
referred to as providers, and protocols which
are used to carry voice signals over the IP
network are commonly referred to as Voice
over IP or VoIP protocols. They may be viewed
as commercial realizations of the experimental
Network Voice Protocol (1973) invented for
the ARPANET providers. Some cost savings are
due to utilizing a single network to carry
voice and data, especially where users have
existing underutilized network capacity that
can carry VoIP at no additional cost. VoIP
to VoIP phone calls are sometimes free, while
VoIP to public switched telephone networks,
PSTN, may have a cost that is borne by the
VoIP user.
Voice over IP protocols carry telephony signals
as digital audio, typically reduced in data
rate using speech data compression techniques,
encapsulated in a data packet stream over
IP. There are two types of PSTN to VoIP services:
Direct Inward Dialing (DID) and access numbers.
DID will connect the caller directly to the
VoIP user while access numbers require the
caller to input the extension number of the
VoIP user.
Advantages of VOIP:
1. The cost of internet telephone is typically
quite lower than standard phone service.Savings
are also seen in Long Distance and International
calls, which are
inexpensive.
2. Enhanced calling features (such as Caller
ID) are normally included in service
plans with no additional charges.
3. VOIP supports high-quality sound transmission.
4. VOIP provides the ability of the subscriber
to make calls from remote locations as long
as there is an internet connection.
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