1. What is VoIP?
It is the technique used in transferring telephone (voice) signal
over the Internet by using Internet Protocol. It transmits a digitized
version of your voice through IP. The digitized voice information
is sent out over the Internet just like other data. From the Internet’s
standpoint there is no difference between other data and digitized
voice data unless we somehow identify the data and can recognize
the data as a real time signal. Most Internet instant messengers
(like Yahoo, Microsoft) allow voice chat. That’s one of the
types of VoIP. If you have the proper interfacing devices, you can
even use an analog phone for chat with these services. While these
are technically VoIP, they aren’t quite what the world is
looking for as a telecom solution. The real world of VoIP is of
course, more complex.
2. What is the difference between my old phone and an IP phone?
The traditional phone we use is an analog phone. It is usually based
on the Bellcore standard. Only two wires are needed for analog phones,
the wire ends in RJ-11 connectors and setup is as simple as plugging
that connector into the wall. An IP Phone is very different, in
fact it is a combination of two things, a digital phone and a system
that converts the digital information into chunks of information
suitable for shipping using the IP. An IP phone requires 8 wires
and ends in an RJ-45 connector and unlike the analog phone; setup
requires a lot more than just plugging that connector into the wall.
3. What are the advantages and disadvantages of VoIP?
- You can make a call anywhere the Internet can reach
- Per minute cost savings and equipment cost savings on the PBX
- It has more features that it has adopted from Internet Technologies
- Works with PCs, regular/cordless phones, faxes & soon wireless
- Very simple to setup & use
- Security, all the same risks as can be found with any IP Technology
- SIP phones cannot share extensions, one SIP phone per extension
- Delay time, Echo
- You require some form of IP service to make a phone call
4. VoIP Telephone Glossary
Attendant console: The larger, specialized phone an operator or
attendant uses to answer incoming calls and route them to the
appropriate extension. In an IP PBX, this may be replaced by
software running on a PC
Centrex: A traditional business telephone service that a local
telephone company offers from a local central office. This is
essentially a normal single-line telephone service with advanced
CSU/DSU (channel service unit/data service unit): A device that
terminates a digital channel. In this context, the device sits
between the voice T1 line and the IP PBX.
Find-me/follow-me: A feature that allows calls to find you wherever
you are, ringing multiple phones (such as your cell phone, home
phone, and work phone) all at once. Such presence features are found
in IP PBXs and offered by some hosted services. You activate them
pressing a soft key.
Gateway In VoIP systems: a network device that converts voice and
fax calls in real time from a public switched telephone network
(PSTN) to an IP network: A gateway can also convert calls between
branch offices to VoIP so they can travel over the Internet.
High-availability: Refers to devices or deployment strategies
designed to provide access to fully functioning systems at all
times. One HA strategy is to cluster devices so that the primary
device can fail over to the secondary one if necessary.
IP Centrex or hosted voice: An IP voice service delivered by an
service provider or a phone company. On the surface it is like
old-fashioned Centrex, but the features are much richer and the
price is usually much lower.
IP PBX (Internet Protocol private branch exchange): A private
telephone switching system that performs the same basic functions
a traditional PBX but operates using IP, making it easier to add
KTS (key telephone system): A system in which the telephones have
multiple buttons representing separate phone lines. Users select
external phone and intercom lines directly through these buttons.
KTS solutions are less expensive and less flexible than PBX
PBX (private branch exchange) A private telephone switching system
that connects outside phone lines from a telecommunications provider
to extensions within a building or office, as well as providing
features as call forwarding and paging. Where older proprietary
systems used handsets designed specifically for separate systems,
new PBX devices are interoperable.
PoE (Power over Ethernet): A solution in which networking hardware
transmits electrical power over Category 5 Ethernet cable or better.
This eliminates the need for AC power cords, minimizing cabling
POTS (plain old telephone service): The typical, familiar
PSTN (public switched telephone network) The combination of local,
long-distance, and international carriers that make up the worldwide
QoS (quality of service): The ability of a network (including
applications, hosts, and infrastructure devices) to deliver traffic
with minimum delay and maximum availability.
SIP (Session Initiation Protocol): An Internet Engineering Task
(IETF) standard for initiating, maintaining, and terminating an
interactive user session involving video, voice, chat, gaming,
virtual reality and more.
Soft keys: Buttons on a telephone handset that can be programmed
perform various functions—such as speed dialing or
conferencing—depending on the interface on the handset's screen.
Soft phone: IP telephony software that lets users send and receive
calls from non-dedicated hardware such as a PC or Pocket PC device.
It is typically used with a headset and microphone.
VoIP (Voice over IP):The process of making and receiving voice
transmissions over any IP network. IP networks include the Internet,
office LANs, and private data networks between corporate offices.
The main advantage of VoIP is that users can connect from anywhere
and make phone calls without incurring typical analog telephone
charges, as for long distance.