VoIP glossary


ADSL: Asymmetric Digital Subscriber Line

Analogue Terminal Adaptor is a small device that enables your standard telephone to make and receive calls over your broadband Internet connection. It’s simple to use and plugs directly in to your broadband router and your normal analogue phone. ATAs are often sold combined with routers.


Dial-up Internet technologies require a phone call to connect you to the internet. When you finish your session the connection is terminated. An always-on service means the connection to the Internet remains open all day every day. This type of service is usually charged at a flat rate per month. You will also need a piece of equipment called a router to manage your connection.


In relation to VoIP analogue refers to pre-digital phones and systems. Virtually all new phones are digital, although many can also use analogue networks.

APN: Access Point Name

An Access Point Name (APN) is the name of a gateway between a GPRS, 3G or 4G mobile network and another computer network, frequently the public Internet. A mobile device making a data connection must be configured with an APN to present to the carrier.

ATA: Analogue Telephone Adaptor

This is a small device that enables your standard telephone to make and receive calls over your broadband Internet connection. It’s simple to use and plugs directly in to your broadband router and your normal analogue phone. ATAs are often sold combined with routers.

Audio Conferencing

The original technology used for audio teleconferencing was based on PBX (Private Branch Exchange) conferencing circuits. Setting up conference calls through the PBX is cumbersome, the voice quality degrades as the number of people on a call increases, and there are capacity limitations, so specialized conference bridges were developed to improve capacity and voice quality.
Conference bridges, however, require trained operator intervention to schedule and invoke most features. As a result, individual corporations found the cost of ownership prohibitive. Today’s PC-based systems provide the freedom of conference bridges.

By installing a conference server on your voice networks, you can set up, attend, and manage your own conferences over any touch-tone telephone and users can schedule meetings using desktop software from their e-mail systems, or from a web browser. See how easy it is here.

Audio Menu

A verbal choice provided by a recording over the phone. Audio choice menus are common in automated attendant, IVR and fax-on-demand systems. They are prompts for caller input. Audio menus can instruct you to speak commands or press keys on a touch-tone keypad as commands.

Auto Attendant

An automatic response system that presents voice options such as “Press 2 for sales”, “Press 5 for Lisa”, etc., which handles incoming calls and sends them to the appropriate phone or message.

Bandwidth and Speed

Bandwidth gives you an indication of the speed capabilities of your broadband connection. This speed is measured in kilobits per second (Kbps). Old dial-up modems have a maximum data rate of 56 Kbps. Broadband services begin with data speeds of 512 Kbps. So even at the lower end of the scale you can see how much faster broadband is. If you see a 2 Mbps connection advertised this means it is 2000 Kbps. These speeds cannot be guaranteed as your connection will more than likely be shared with other people.


Broadband is high-speed Internet access that you access through a cable or DSL modem. It has a continuous connection to the Internet at much faster speeds than dial-up.

BOYD or Bring Your Own Device

BOYD is a policy of permitting employees to bring personally owned devices (laptops, tablets, and smartphones). According to our ICT report, almost 60% of companies already do so.

Call Forwarding

A phone service feature that allows the user to forward a phone call to another phone number. For example, you can forward your home phone number to your mobile number so you never miss a call.

Call Logs

These are detailed call records. With Blueface you can view these on-line by logging in to your account. They contain information on call: duration, destination, origination and price.

Call Waiting

Call waiting puts your first call on hold while you answer the second. While you are on the phone a beep tone alerts you to another incoming call. You can then put your first call on hold and take the second call. Any calls that you do not choose to take will go to your voice mail.

Cloud Telephony

Cloud Telephony is the technology that moves your business phone system to the cloud and delivers web-based or automated telephone applications.
It is a voice and messaging service that replaces the need for the conventional business telephone system.
Cloud telephony products include:

  • Hosted IVR (Interactive Voice Response)
  • Voice Broadcasting
  • Call Tracking Software
  • Private Branch
  • IP-PBX (Private Branch Exchange)

Cloud telephony allows you to make and receive multiple calls & SMSes simultaneously, without having to invest in any additional infrastructure. Services like IVR, Call Recording, Bulk SMS, event based calling, etc. are only some among the many features cloud telephony has to offer.

Codec (Coder Decoder)

In VoIP, it is a voice compression-decompression algorithm that defines the rate of speech compression, quality of decompressed speech and processing power requirements.

G.711 – This vocoder is used with PSTN lines. It is commonly called PCM (Pulse Code Modulation). There are two types of algorithm: u-law used in North America and Japan, and A-law used in the rest of the world. This vocoder algorithm produces a bit rate of 64 Kbits/second and has no silence suppression. This means silence is transmitted and occupies bandwidth.

G.723 – This vocoder is commonly used in VoIP gateways. It is called a Multi-rate Coder and it has two bit rates, 5.3 and 6.4 Kbits/second. This vocoder algorithm has silence suppression, meaning silence is not transmitted and does not occupy bandwidth.

G.726 – This vocoder frequently called ADPCM (Adaptive Differential Pulse Code Modulation) is used in the NACT IPAX gateway for the playback of voice messages such as authorisation code and destination number prompts. This vocoder algorithm can produce bit rates of 16, 24, 32, and 40 Kbits/second. The NACT IPAX voice prompts are recorded at 32 Kbits/second. This vocoder has no silence suppression, meaning silence is transmitted and occupies bandwidth.

G.727 – This vocoder oftentimes called Variable-Rate ADPCM is available in the NACT IPAX VoIP vocoder suite. This vocoder algorithm allows bit rates of 16-40 Kbits/second for sending and receiving voice. The bit rates can be variable sin each direction. It has no silence suppression.

G.728 – This vocoder sometimes known by the abbreviation LD-CELP (Low-Delay Code Excited Linear Prediction) is used in some VoIP gateways. It has a bit rate of 16 Kbits/second.

G.729 – This vocoder often known by the abbreviation CS-ACELP (Conjugate Structure Algebraic-Code Excited Linear Prediction) is used in many VoIP gateways. It has a bit rate of 8 Kbits/second. This vocoder algorithm has silence suppression meaning silence is not transmitted and does not occupy bandwidth.


Congestion occurs when there is too much traffic on the Internet or a specific site. This slows all webpage requests down and causes delays in downloading files and viewing information.

Conference Bridge

A device used to connect multiple parties over the phone. A proctor or operator can man conference bridges or they can be supervised. There are standalone conference bridges and conference bridge functions built in to some PBXs (Private Branch Exchange).
These systems have circuitry for summing and balancing the energy (noise) on each channel so everyone can hear each other. More sophisticated conference bridges have the ability to “idle” the transmit side of channels of non-speaking parties.

Contention Ratio

When you have a broadband connection there is a connection path between you and the Internet Service Provider. This connection path that carries data is referred to as contention. Many users will be using the same connection so when service providers quote a contention ratio of say 50:1 this means 50 other users will be using the same connection as you.
This could affect you at peak usage times as the connection could become congested. Normally, however, you can expect this not to have a significant impact on your connection and broadband speed.

DHCP: Dynamic Host Configuration Protocol

It is a communications protocol that lets network administrators centrally manage and automate the assignment of Internet Protocol (IP) addresses in an organisation’s network. Using the Internet Protocol, each machine that can connect to the Internet needs a unique IP address, which is assigned when an Internet connection is created for a specific computer. Without DHCP the IP address must be entered manually at each computer in an organisation and a new IP address must be entered each time a computer moves to a new location on the network. DHCP lets a network administrator supervise and distribute IP addresses from a central point and automatically sends a new IP address when a computer is plugged into a different place in the network.

DID: Direct Inward Dialling

The ability to make a telephone call directly to an internal extension without having to go through an operator.

DNS: Domain Name System

It resource record which specifies a regular expression based rewrite rule that, when applied to an existing string, will produce a new domain label or Uniform Resource Identifier (URI).


Downloading information is usually used to describe transferring information/data from the Internet. When you download a file like an email or web page it copies from a remote computer to your computer.

Digital Subscriber Line (DSL)

A high-speed digital switched service that uses existing copper pairs to connect subscriber CPE (customer premises equipment) to the CO (central office). DSL handles more data downstream (data flowing towards the subscriber) than upstream (flowing towards the network).


DTMF (dual tone multi-frequency) is the signal or noise the phone keypad makes when you press the touch keys. When you press a key it generates two specific frequencies so a voice cannot imitate the tones. These tones are used for signalling the telephone exchange.


A method of networking computers in a local area network (LAN).

Ethernet Cable

This is a cable used in networking computers. It can carry data like basic voice services and connect your computer to a router to access the Internet.


A system designed to prevent unauthorized access to or from a private network. Firewalls can be implemented as hardware, software, or a combination of both. All messages entering or leaving pass through the firewall, which examines each message and blocks those that do not meet the security criteria specified on the firewall.

Flex Buttons

Panasonic phones have flex(ible) buttons on the sidecar menu that allow you to dial directly internal or external numbers saved on your phone. You may upload your phonebook through a user-friendly online interface.

Full Duplex

In telephony and data communications, full duplex means the ability for both ends of a communication to simultaneously send and receive information without degrading the quality of the content.


In IP telephony a gateway is a network device that converts voice and fax calls in real time between public switched telephone networks (PSTN) and an IP network. The primary functions of an IP gateway include voice and fax compression/decompression, packetisation, call routing, and control signalling.

GUI – Graphical User Interface

It is a computer interface that uses icons or pictures to help users navigate and control both services.

IP Address: Internet Protocol Address

An IP address is a unique address that certain electronic devices use in order to identify and communicate with each other on a computer network. Any participating network device including routers, switches, computers, time-servers, printers, Internet fax machines, and some telephones have their own unique address. An IP address acts as a locator for one IP device to find another to interact with.

ISDN: Integrated Services Digital Network

This is a digital telephony and data-transport service offered by regional telephone carriers. ISDN involves the digitisation of a telephone network, which permits voice, data, text, graphics, music, video, and other source material to be transmitted over existing telephone wires.

ISP: Internet Service Provider

A provider of Internet access. This can be for broadband or dial-up.

IVR: Interactive Voice Response

Is an automated software-based telephone information system that speaks to callers using a mix of fixed voice menus and real-time data accessed from databases. Callers interact with an IVR by making touch-tone keypad selections or speaking words or short phrases. IVR systems are used to route callers to specific personnel or departments, conduct polls or provide information, such as billing information or bank balances.

Internet Telephony

Any means of transmitting the human voice (real-time or near real-time) over the Internet. There are several components: 1) On the client side, a multimedia-equipped PC with special client software will digitize your voice. This can be done with a voice modem or other voice encoding method; 2) A direct or dial-up connection to the Internet allows your voice to be transmitted in packet form to its destination; 3) Connection with the far side is achieved by IP address search, common servers or beacons to identify the called party (and to “ring” that person’s phone); 4) A similar arrangement on the far end completes the call and allows both parties to speak. There are also PSTN/Internet gateways that allow regular telephone callers to make phone-toInternet-to-phone connections. There are PC-to-phone connections and phone-to-PC connections.


In VoIP jitter is the variation in the time between packets arriving caused by network congestion, timing drift, or route changes. A jitter buffer can be used to handle jitter.

LAN: Local Area Network

A local area network is a computer network covering a local area, like a home, office or small group of buildings such as a college or hospital.


In a network latency, a synonym for delay, is an expression of how much time it takes for a packet of data to get from one designated point to another. Latency is measured by sending a packet that is returned to the sender and the round-trip time is considered the latency.


A modem is a device for sending computer data over a voice phone line.


Two or more computers that are connected so users can share files and devices (for example, printers, servers and storage devices).

P2P: Peer to Peer

This is a program that allows a computer to link to another computer via the Internet. Often information and data can be downloaded and exchanged.


A technique for routing data through a network by encapsulating data in to packets. These packets are then labelled with addresses and routing information and forwarded until they reach their intended destination.

PBX: Private Branch Exchange

It is a very small specialised switch. It permits any attached telephones to call each other using shorter numbers and requires the caller to select an “outside line” to make calls outside the switch. A VoIP based PBX is a very common device which can be hardware or a software at the user’s end that manages calls and diverts.


Power-cycle is a euphemism for asking you to switch off a device and switch it back on again.


There are 2 kinds of Ports, Physical Port and Logical Port. A physical port is located on computer and telecommunication devices where you can physically connect to some other device, usually with a socket and plug of some kind. Logical port is a term used in programming. It is a logical connection place like on a router interface when you login you see SIP ports or RTP ports, Ports required by Blueface are UDP 5060-5061 for VoIP and UDP 10000-20000 for voice.

PPP: Point-to-Point Protocol

PPP is a connection oriented protocol that establishes a link between two communication devices that encapsulates data packets (such as Internet packets) for transfer between two communication points. PPP allows end users (end points) to setup a logical connection and transfer data between communication points regardless of the underlying physical connection (such as Ethernet, ATM, or ISDN).


A protocol is a formalised set of rules that computers use to communicate. This strictly defines procedure and message formats allowing two or more systems to communicate over a transmission medium.


A proxy or proxy server is basically another computer which serves as a hub through which internet requests are processed. By connecting through one of these servers, your computer sends your requests to the proxy server which then processes your request and returns what you were wanting. In this way it serves as an intermediary between your home machine and the rest of the computers on the internet.>

PSTN: Public Switched Telephone Network

The world’s collection of interconnected public telephone networks, both commercial and government-owned.

QoS: Quality of Service

QOS ensures the quality of your voice calls even when your broadband connection is being used for other items like downloading music or surfing the web. QOS always retains a specific amount of your bandwidth for voice calls so you can talk without any interruption or interference.


Is a term used to describe restarting your computer and operating system.


Is a piece of hardware that directs information to your computer this is what connects you to an Internet service provider for Internet access.


SIP is a protocol designed to allow personal computers to place telephone calls on the Internet. It is a standard protocol for initiating an interactive user session that involves multimedia elements such as video, voice, chat and gaming.


A Softphone is software installed on your computer that enables the use of VoIP without any hardware. You will need a headset or microphone and headphones to make phone calls. It allows you to make and receive phone calls without having a traditional phone.


A switch is a device that connects two separate data paths together. For example to connect two computers to one printer.


Session Initiation Protocol (SIP) trunking is the use of voice over IP (VoIP) to facilitate the connection of a private branch exchange (PBX) to the Internet. In effect, the Internet replaces the conventional telephone trunk, allowing an enterprise to communicate with fixed and mobile telephone subscribers worldwide.

Unified Communications

Unified Communications (UC) is equipment, software and services that facilitate the interactive use of multiple enterprise communications methods. UC products integrate communications channels (media), networks and systems, as well as IT business applications.
UC is not necessarily a single product, but a set of products that provides a consistent unified user interface and user experience across multiple devices and media types.
Unified Communications tools can include services such as:

  • instant messaging (chat),
  • presence information (when a software or a tool publishes a presence state about current communication status),
  • voice (including IP telephony),
  • mobility features (including extension mobility and single number reach),
  • audio, web & video conferencing,
  • desktop and data sharing (including web connected electronic interactive whiteboards),
  • call control and speech recognition with non-real-time communication services such as unified messaging (integrated voicemail, e-mail, SMS and fax).

Unified Communication is especially useful in an office environment as it can help employees in a variety of contexts:

  • Traditional office environments, with users on computers and using desk phones or softphones and individual webcams.
  • Enterprise conference rooms equipped with speaker phones, a shared display system, and a shared camera system (which might be traditional conferencing systems or high-end telepresence systems).
  • Remote employees working from mobile devices including tablets and smartphones, using the audio and video native to the device.

To find our more how Unified Communications can help your business watch this video.


VoIP is essentially the new standard for phones a bit like HD for televisions except it’s actually cheaper than the old telephone lines. The technology has actually been around for a while but it’s the improvements in broadband that have created huge growth in the past few years.
VoIP is basically Internet telephony: instead of your calls running through Eircom’s copper line coming in to your office, we process calls through the Internet.

As VoIP works through the Internet the one thing to make sure of is that you have a solid broadband connection. Your Internet may be good enough or could require to be upgraded to facilitate Blueface calls. Read more about VoIP here.

WiFi: Wireless Fidelity

Refers to products that can connect to each other without wires. These can include routers and laptops.

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