Position Paper
AN INTRODUCTION TO NETWORK TELEPHONY
WHY IP-PBX SYSTEMS
ARE GOOD FOR BUSINESS
Position Paper
AN INTRODUCTION TO NETWORK TELEPHONY
WHY IP-PBX SYSTEMS ARE GOOD FOR BUSINESS
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 (IP-PBX) 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 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
transmissions.
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
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.
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 protocol
Internet protocol telephony – telephony using internet protocols instead of those of PSTN
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
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
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.
TECHKNOWPARTNERS, LLC 4659 SOUTH LAKESHORE DRIVE, SUITE K
TEMPE, ARIZONA 85282 USA www.techknowpartners.com
(480) 553-8951
