Getting Down to Business
with VoIP
In This Part
Understanding the basics of VoIP
Making full use of VoIP and its many features
Getting to know your IP phone
Technological innovation is hurling itself upon us once
again. This time it is coming in the form of improving the
way we make telephone (voice) calls. It brings with it several
new capabilities that really change the meaning of the phrase
telephone call. VoIP is the name of this new communications
technology. VoIP stands for Voice over Internet Protocol.
Basically, VoIP means “voice transmitted over a digital network.”
VoIP is often referred to as IP Telephony because it uses the
latest innovations with the popular and familiar IP protocols to
make possible enhanced voice communications throughout the
enterprise. IP networking supports corporate, private, public,
cable, and even wireless networks. IP Telephony unites an
organization’s many locations—including mobile workers—
into a single converged communications network.
And by the way, don’t let the “voice” part of the acronym fool
you — telephony calls using VoIP go above and beyond the
call of duty. When it comes to placing telephone calls, VoIP
provides a range of support services and features unequalled
in the world of telephony. More on that later in this part.
How Does VoIP Work?
VoIP, or Voice over Internet Protocol, means basically what the
acronym states: Voice travels over the Internet. When VoIP
was first developed, it worked only with the Internet and nothing
but the Internet so help us all. Today, VoIP operates over
most network types, including those used throughout the
corporate sector. But the “I” has stuck with the acronym. The
“P” represents the term Protocol. Protocol refers to the type
of rules that the network uses to send and receive signals.
These signals are the high and low electrical or optical pulses
often represented by the more familiar 1s and 0s of digital
networking.
IP Telephony works by converting voice communications into
data packets. Conveniently, it runs on the popular Ethernet
LAN (local area network) technology, which currently supports
over 96 percent of all companies’ needs for LANs.
Circuit-switched telephony
Before digital networking took off, everyone had to use the
one and only Plain Old Telephone Services (POTS). POTS runs
over a network called the Public Switched Telephone Network
(PSTN). The PSTN has been around since Mr. Bell invented the
telephone. That is why most companies today have POTSrelated
systems in place. These POTS telephone systems use
the old tried-and-true (and more expensive) method of telephone
service known as circuit-switched.
Believe it or not, a good illustration of POTS and PSTN is the
experiment where your fifth-grade teacher had you take two
tin cans and a length of wire to create an archaic telephone
system. As strange as it seems, this antiquated method of
telephony is the principal means underlying the operation of
POTS operating over the PSTN.
What changes in the real POTS-based telephony system is
the number, length, diameter, and type of wire or cables used.
These elements have grown immensely in variety and type.
In addition, the types of telephone equipment have changed
dramatically both at the customer end and at the carrier
provider end. But POTS telephony continues to use “circuitswitched”
rules (or protocols) of operation.