Why IP-PBX is good for business
Position Paper
Position Paper
Network telephony embraces both the use of the public switched
telephone network (PSTN) and the internet for both voice and data
communications. An Internet Protocol Private Branch eXchange (IPPBX) is a telephone system designed to operate over a data network in
conjunction with the PSTN to deliver both voice and video content.
The term “IP” refers to “internet protocol.” The term “VoIP” refers to
“voice over internet protocol” - the definition relates to the protocol, not
necessarily the internet; the protocol can be used on intranets and local
area networks, in addition to both private and public wide area networks.
An IP-PBX system combines traditional PBX functionality and voice over
internet protocols enabling a business to leverage its intranet to allow
users to make internal calls, and external local, long distance, and
international calls via the PSTN.
Unlike “hosted VoIP” services, whereby the servers and other equipment
are hosted and managed by VoIP providers at remote locations, IP-PBX
systems are hosted locally with private connections to phone companies.
As a consequence they avoid the dropped and jittery calls associated with
hosted VoIP solutions, and do not suffer from call quality degradation as
more phones are added. IP-PBX systems use either the primary rate
interface (PRI) or the session initiation protocol (SIP) for establishing,
monitoring, and terminating phone calls. SIP connections usually cost less
than those of PRI.
IP-PBX systems are much easier to install than traditional PBX systems.
They are easier to manage by using a web-browser interface that provides
current call and systems statuses and historical usages. The SIP standard
enables the use of non-proprietary IP phones that can be “hot plugged”
into any ethernet connection on the intranet, without changing extension
numbers. SIP also allows for easy roaming.
IP-PBX systems have a lower total cost of ownership than both traditional
PBX and hosted VoIP solutions because they do not require separate voice
and data networks, incur lower long distance costs, and have no
incremental costs as more phones are added. They offer at least the same
functionality as traditional PBX systems, including auto attendant, call
queues, call recording, and voicemail.
A PBX serves a particular business as opposed to a telephone exchange
operated by a common carrier or telephone company, connecting outside
calls with internal extensions, and internal extensions with each other.
Originally PBXs were operated manually, but have become automated
over time. Automated PBXs were special purpose computerized devices.
A traditional PBX requires separate networks for data and voice
An IP-PBX is a communications server that uses the VoIP protocol. It is
able to switch VoIP calls between users on a local network, and allows all
users to share external phone lines. The server hosts a server-side
operating system, such as Linux, Unix, or Windows, and an application,
such as Asterisk, which delivers the PBX functionality managed through a
graphical user interface, such as Free PBX.
IP-PBX systems can be configured in different ways:
Single site – with an IP-PBX connected to the PSTN using a PRI
or SIP-based carrier for typically 2 to 50 phones
Multiple site – a single phone system connecting multiple sites
through extensions – a IP-PBX can be placed at a central
(corporate) office, and can also be placed in branch offices,
connected via the PSTN; the phones are connected through a
private WAN or MPLS – small sites (branches) may have
approximately 1 to 10 phones (without an IP-PBX) and larger
sites (branches) may have approximately 11 to 50 phones with a
local on-premise IP-PBX
For high availability, multiple data synchronized IP-PBXs may
be placed at each site with redundant carrier connections to the
IP-PBX systems provide for unified messaging – the ability to receive all
messages, including email, fax, and voice in one place. They can also
provide for integration with applications, such as CRM.
IP-PBX systems are good for business because they are easy to administer,
are fully functional private branch exchanges, and they have a lower total
cost of ownership than traditional and hosted VoIP offerings.
Glossary Of Terms
ACD – automatic call distribution
ATA – analog phone adapter
Centrex – central exchange – a “hosted” PBX-like offering by a telephone company
CTI – computer telephony integration
DID – direct inward dialing
Ethernet – networking technology subdividing streams of data into packets called
frames using twisted pairs
Extranet – private network that allows limited authorized pubic assess
Hosted VoIP – VoIP servers and other equipment hosted and managed by providers
at a remote location accessed via the internet
Internet – public network of interconnected networks using the standard internet
Internet protocol telephony – telephony using internet protocols instead of those of
Internet telephony – telephony over the internet including fax, SMS, and voice
instead of over the PSTN
Intranet – private network of interconnected networks using the standard internet
protocol – can range from an internal website to a large portfolio of networks within
an enterprise
IP – internet protocol
ISDN – integrated services digital network – standards for allowing multiple digital
data, video, and voice communications over traditional PSTN lines
IVR – interactive voice response
LAN – local area network within limited areas of enterprises, facilities,
geographies, and political boundaries
MPLS – multiprotocol label switching – a mechanism for directing data between
network nodes using labels instead of addresses that require lookups in routing
Packet switching – grouping transmitted data, regardless of type, into blocks
PBX – private branch exchange
POTS – plain old telephone system
PRI – primary rate interface – service level for multiple calls over an ISDN network
PSTN – public switched telephone network
Roaming – enabling connectivity between home and other locations
SIP – session initiation protocol – controls communications sessions for video and
voice calls
Softphone – software using the VoIP protocol that enables users to make phone calls
over the internet from computers such as desktops, laptops, and smartphones
T1 – a digital multiplexed telecommunications carrier system
Trunk failover – rerouting of calls to a redundant carrier after a connection to a
phone service provider fails
Trunking – providing network access to multiple users at the same time by either
sharing lines or frequencies
Twisted pair – forward and return conductors are twisted together to cancel out
electromagnetic interference
Unified communications platform – tying voice and data applications, such as
voicemail-to-email and application-to-phone integration, including conferencing
and faxes
VoIP – voice over internet protocol – note: the definition relates to the protocol, not
necessarily the internet; the protocol can be used on intranets and local area
networks, in addition to private and public wide area networks
WAN – wide area network across enterprise, facility, geographic, and political
boundaries, and usually connecting LANs
Web-based phone user portal – place for managing the functions of a user's phone
TechKnowPartners, LLC is a technology services firm joint venture of Nigel Brooks,
LLC and Speedy Turtle Computers, LLC. The firm combines the business and
technology strategy consulting talents of Nigel A.L. Brooks with the technology
infrastructure design, installation, and support talents of Dylan M. McKinstry.
The firm is a technology strategy and infrastructure professional services provider with
experience in multiple industries and with multiple platforms including Android, Apple,
Linux, and Microsoft. The firm serves small-to-middle market businesses in the
Tempe, Arizona area, delivering complete technology solutions that leverage
client/server, cloud, and mobile platforms.
A primary area of focus of the firm is IP-PBX (Internet Protocol - Private Branch
eXchange) systems, an emerging business telephony technology with a lower total
cost of ownership than traditional PBX systems.
The firm is a VoIPstar Systems authorized dealer that make business communications
more effective. The firm is a member of the Microsoft® partner network.
Working with you today for your technology needs tomorrow
Technology Strategy and Infrastructure Professionals
Consulting l Design l Installation l Support
(480) 553-8951
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