VoIP and IP telephony
A strong unified communications strategy starts with voice technology. Explore all facets of enterprise telephony, including hardware and devices, architecture, and standards and protocols like SIP and H.323.
Top Stories
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Tip
25 Nov 2024
Understanding VoIP multi-codec transcoding
VoIP relies on codecs that permit the seamless connection between callers and networks. But there are many codecs and multiple endpoint devices. Enter VoIP multi-codec transcoding. Continue Reading
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Feature
07 Jun 2024
The history of telephones explained
The telephone, once a marvel for the rich, became a household necessity. Now, mobile phones and web calls have relegated landlines to near-forgotten relics. Continue Reading
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Answer
20 Mar 2013
What are the different types of private branch exchange systems?
The types of PBX systems available shifted after the advent of Internet Protocol, according to IP telephony expert Jon Arnold. Continue Reading
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Answer
05 Mar 2013
Are there advantages to using the public switched telephone network?
You may have to sacrifice some advantages of the public switched telephone network if you switch to VoIP, says telephony expert Jon Arnold. Continue Reading
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Answer
19 Nov 2012
How does VoIP performance differ over LAN, WAN and other networks?
Environment affects VoIP performance, so it's important to consider how VoIP best fits in your environment is important, our UC strategies expert explains. Continue Reading
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Definition
09 Nov 2012
scalable video coding (SVC)
Scalable video coding (SVC) is an extension of the H.264 (MPEG-4 AVC) video compression standard for video encoding. Continue Reading
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Answer
03 Aug 2010
The value of toll bypass in the enterprise
IP telephony expert Jon Arnold explains the value of toll bypass in an IP telephony setup, detailing why enterprises should consider it as an option while tempering cost-savings expectations. Continue Reading
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Definition
26 Sep 2008
Ethernet/IP (Ethernet Industrial Protocol)
Ethernet/IP (Ethernet Industrial Protocol) is a network communication standard capable of handling large amounts of data at speeds of 10 Mbps or 100 Mbps, and at up to 1500 bytes per packet. Continue Reading
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Definition
07 Mar 2008
SDP (Session Description Protocol)
SDP (Session Description Protocol) is a set of rules that defines how multimedia sessions can be set up to allow all end points to effectively participate in the session. In this context, a session consists of a set of communications end points along with a series of interactions among them... (Continued) Continue Reading
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Definition
07 Mar 2008
call control
Call control is a process that is used in telecommunications networks to monitor and maintain connections once they have been established. Continue Reading
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Definition
07 Mar 2008
call signaling
Call signaling is a process that is used to set up a connection in a telephone network. Continue Reading
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Definition
07 Mar 2008
call deflection
Call deflection is a feature of voice over IP (VoIP) that automatically redirects a call from the called endpoint to another endpoint (usually a voice mailbox) when the called endpoint is busy. Continue Reading
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Definition
07 Mar 2008
call detail record (CDR)
A call detail record (CDR) in voice over IP (VoIP) is a file containing information about recent system usage such as the identities of sources (points of origin), the identities of destinations (endpoints), the duration of each call, the amount billed for each call, the total usage time in the billing period, the total free time remaining in the billing period, and the running total charged during the billing period. Continue Reading
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Definition
07 Mar 2008
hop off
Hop off is a term used in telecommunications that refers to a point at which a signal or call leaves a network and moves to another network. Continue Reading
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Definition
07 Mar 2008
Skinny Client Control Protocol (SCCP)
Skinny Client Control Protocol (SCCP) is a Cisco proprietary standard for terminal control for use with voice over IP (VoIP). Continue Reading
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Definition
07 Mar 2008
hairpinning
In general telecommunication, hairpinning is returning a message from an origin endpoint back in the direction it came from as a way to get it to its destination endpoint. Continue Reading
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Definition
07 Mar 2008
jitter buffer
In voice over IP (VoIP), a jitter buffer is a shared data area where voice packets can be collected, stored, and sent to the voice processor in evenly spaced intervals. Continue Reading
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Definition
07 Mar 2008
centrex (central office exchange service)
Centrex (central office exchange service) is a service from local telephone companies in the United States in which up-to-date phone facilities at the phone company's central (local) office are offered to business users so that they don't need to purchase their own facilities. Continue Reading
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Definition
06 Mar 2008
IP PBX (private branch exchange)
An IP PBX is a private branch exchange (telephone switching system within an enterprise) that switches calls between VoIP (voice over Internet Protocol or IP) users on local lines while allowing all users to share a certain number of external phone lines. Continue Reading
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Definition
06 Mar 2008
virtual phone number
A virtual phone number is a telephone number is used to route calls to the user's actual phone number or numbers. Continue Reading
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Definition
06 Mar 2008
regional Bell operating company (RBOC)
Regional Bell operating company (RBOC) is a term describing one of the U.S. regional telephone companies (or their successors) that were created as a result of the breakup of American Telephone and Telegraph Company (AT&T, known also as the Bell System or "Ma Bell") by a U.S. Federal Court consent decree on December 31, 1983. The seven original regional Bell operating companies were Ameritech, Bell Atlantic, BellSouth, NYNEX, Pacific Bell, Southwestern Bell, and US WEST. Each of these companies owned at least two Bell operating companies (Bell operating company). Continue Reading
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Definition
06 Mar 2008
Vonage
Vonage is a communication platform as a service (CPaaS) provider for consumers and businesses that makes it possible for customers to connect and communicate on any device through cloud-hosted voice, video, chat and short message service (SMS). Continue Reading
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Definition
06 Mar 2008
softphone (soft client telephone)
A softphone (software telephone) is an application program that enables voice over Internet Protocol (VoIP) telephone calls from computing devices. In the enterprise, softphones are sometimes referred to as soft clients. Continue Reading
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Definition
06 Mar 2008
CLEC (competitive local exchange carrier)
In the United States, a CLEC (competitive local exchange carrier) is a telephone company that competes with the already established local telephone business by providing its own network and switching. Continue Reading
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Definition
06 Mar 2008
dedicated line
A dedicated line is a telecommunications path between two points that is available 24 hours a day for use by a designated user (individual or company). Continue Reading
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Definition
23 Jul 2007
Erlang B
Erlang B is a modeling formula that is widely used in call center scheduling... (Continued) Continue Reading
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Answer
22 Jul 2007
What can a VoIP phone do that a landline phone cannot?
This expert response outlines the basic differences between a VoIP phone and a POTS phone. Continue Reading
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Tip
05 Mar 2007
How silence suppression saves WAN bandwidth
Silence suppression, or voice activation detection (VAD), technology is used to save WAN bandwidth used by VoIP traffic, while comfort noise generation (CNG) counteracts negative affects on VoIP speech quality. Continue Reading
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Tip
12 Feb 2007
VoIP bandwidth: Calculate consumption
The bandwidth needed for VoIP transmission depends on compression technology, packet overhead and the network protocol used. In this tip, learn how to calculate how much bandwidth your VoIP implementation will need. Continue Reading
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Tip
22 Jan 2007
How voice compression saves bandwidth
Compression of voice traffic can save bandwidth on your IP network, but can cost quality or cause delays. Learn more about the CODECs or standards for voice compression -- and their effect on call quality -- in this tip. Continue Reading
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Tip
18 Aug 2005
Defining traffic telecommunications style
There are three types of traffic: voice, data and image -- each with its own set of requirements for transmission. Find out here how these different types of traffic are quantified. Continue Reading
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Answer
27 Jul 2005
What is tromboning?
In this expert reply, Patrick Ferriter explains what tromboning means in VoIP. Continue Reading
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Tip
07 Jul 2005
Turning analog phones into VoIP phones
How an ATA or broadband phone works and what kind of features and performance you can expect from them. Continue Reading
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Tip
02 May 2005
Working with the Layer 2 data link layer in an IP telephony deployment
This IP telephony deployment article provides solutions to performance issues in Layer 2, the data link layer. Continue Reading
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Tip
23 Jun 2004
Policing and shaping within QoS
Learn about the policing and shaping methods within QoS that allow IT professionals to smooth traffic flows for VoIP transmission. Continue Reading
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Answer
09 Feb 2004
What is the difference between gateways and gatekeepers?
Learn what the difference is between a network gateway and a gatekeeper in this Ask the Expert response. Continue Reading