A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

A

ACD

Automatic Call Distribution (i.e.: directing a call to the most appropriate call handler in the shortest possible time, attempting to ensure that the caller is satisfied, that incoming call queues are managed effectively and that the call handling resources are efficiently and effectively used).

ADSL

Asymmetric Digital Subscriber Line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines. ADSL provides high downstream and low upstream. ADSL provides high downstream and low upstream.

ADSL2

ADSL2 is a second generation ADSL product increasing capability of basic ADSL to 12Mbps.

ADSL2+

ADSL2+ or ADSL2 plus as it is sometimes called is an advance on the second generation ADSL product increasing capability of basic ADSL to 24Mbps.

ADSL MAX

ADSL Max is a variation of the earlier supplied ADSL service. MAX is a rate adaptive service which is never fixed, but will continually attempt to get the best speed it can. Earlier rate adaptive services would “bed in” and be fixed over a period of 3 days. ADSL Max is a more sensitive system than earlier ADSL services and due to interference it can reduce the speed below standard “classic” ADSL services.

ADSL PLUS

See ADSL2+.

AES

Advanced Encryption Standard (i.e.: a symmetric 128-bit block cipher data encryption algorithm).

ALG

Application Layer Gateway. A component that provides VoIP-specific firewall capabilities.

Analogue

An analogue signal is a variable signal in terms of time and amplitude.

Analogue line

A PSTN line.

ATA

Analogue Telephone Adapter. An ATA is a device which acts as a hardware interface between a PSTN analogue telephone system and a digital network or IP telephony service.

ATM

Layer 2 WAN technology called Asynchronous Transfer Mode, used as the underlying technology for the UK broadband.

Auto-attendant

Technology that allows a caller to interact with the telephone system by responding to a menu of options. Typically this is a voice-based feature that allows callers to be automatically transferred to extensions or departments by dialing digits.  Also known as IVR (Interactive Voice Response). Back to top ^

B

Bandwidth

In digital systems bandwidth is data rate (e.g.: of channel capacity or network throughput) measured in bits or kilobytes per second.

Battery Back-up

See UPS.

Breakout

When making a VoIP call, when the receiver is on a non-VoIP line, the call must breakout of the VoIP network, typically via an ITSP.

BRI

Basic Rate Interface ISDN service. See ISDN2.

Broadband

Broadband is a general term that is used to describe high bandwidth internet services. It actually applies to any service that has a 256 kbps or faster download speed. Back to top ^

C

Call Barring

The prevention of calls to certain destinations, e.g. overseas calls or calls to premium rate numbers.

CDR

Call Detail Record.

Call Forwarding

Also known as call diversion. By dialling a code, a user can divert incoming calls to another destination. The destination may be another extension, a group of extensions, the operator, or an external number e.g. a mobile phone. Different types of diversion are usually possible, e.g. Diversion of All calls, Diversion on Busy, Diversion on no reply.

Call Hunting

A calling feature for inbound calls that will “roll past” a busy signal or try multiple numbers until the call is answered.

Call Logging

Data recorded about calls made or received through a telephone system.

Call Management

The use of specialist software to analyse and report on call records which are output from a telephone system.

Call Park

A call can be parked by one user and then retrieved by another.

CAT5

An Ethernet cable standard. CAT5 cables contain 4 twisted pairs of copper wire, support 100 Mbps bandwidth and is limited to a maximum recommended run lengths of 100m (328 feet).

CAT5e

An enhanced version of CAT5 variation that supports increased bandwidth. CAT5e cabling is backward-compatible with standard CAT5 cabling.

CAT6

A higher quality version of CAT5 / CAT5e that supports increased bandwidth of up to 1000 Mbps.

CODEC

A Codec digitizes and compresses a voice signal. The most common are G.711 and G.729.

Contention Ratio

The potential maximum demand related to the actual bandwidth. The higher the contention ratio (e.g.:50:1), the greater the number of users that may be trying to use the actual bandwidth at any one time, and therefore, the lower the effective bandwidth offered. Lower convention ratios are better (e.g.:10:1, 5:1).

Convergence

A technological environment in which any combination of voice, video and data using any combination of fixed and mobile services, may be accessed from any location via any device.

CRM

Customer Relationship Management. Usually regarding computer-based applications for managing client information.

CTI

Computer-Telephony Integration. Allows interactions on a telephone and a computer to be integrated or co-ordinated. Back to top ^

D

DDI

Direct Dialling In. A method of directly dialling the person you require even though they may work in a large organisation served by a switchboard.

DHCP

Dynamic Host Configuration Protocol. A protocol that lets one device on a local network, known as a DHCP server, assign (and re-use) temporary IP addresses to the other network devices, typically computers.

DiffServ

DiffServ is a layer 3 QoS method of marking IP packets to differentiate services. This allows different types of data to be treated differently as it is passed through the network on a device by device basis.

DMZ

(A local area network) De-militarised Zone. A “no mans land” within a firewall. This is often extended as a LAN for certain services such as Internet web services.

DNS

Domain Name Server. Typically the IP address of an ISP’s server; a DNS translates the names of websites into their underlying IP addresses.

DSCP

Differentiated Services (DiffServ) Code Point. The use of a part of an IP header to indicate data traffic importance.

DSL

Digital Subscriber Line. This is is a family of technologies that enables copper telephone lines to carry data-streams at high-speeds. Also known as xDSL, the ‘x’ is simply a placeholder which can be replaced to denote different DSL technologies, such as ADSL.

DSLAM

Digital Subscriber Line Access Multiplexer. Equipment located in a local exchange that aggregates the connections of broadband users into one or more link onto an ATM circuit. It is here whatever contention ration the service runs at will occur. Back to top ^

E

E1

A high-bandwidth digital transmission link with a capacity of 2.048 Mbps, used predominantly within ISDN services within Europe. E1 is split into 32 channels each capable of carrying a single voice conversation or data stream.

Echo

Echo occurs when some proportion of either user’s call is echoed back.

Ethernet

Ethernet is the most widely-installed local area network (LAN) technology. Most new computers have this capability pre-installed or can be upgraded to take advantage of this connection method. Ethernet is also available on the WAN with leased line technology. Back to top ^

F

Firewall

A security system that controls what type of data types are passed through it. This might be a hardware device protecting a network from another less trusted network such as the internet. Or it can be a software device running on a computer.

Follow Me

A call feature that allows calls to find you wherever you are, ringing multiple phones all at once. Further information can be found in our news article ‘Find Me, Follow Me’. How did you manage without it….

FTP

File Transfer Protocol. A standard protocol for sending files between computers via a TCP/IP network / Internet.

FXO

Foreign Exchange Office. A device / card that connects to the PSTN and is the interface offered on a standard telephone. In VoIP, such a device is used to connect an IP PBX system to standard analogue telephone line(s).

FXS

Foreign Exchange Station. A device / card that connects to an ‘end-user’ device such as a fax machine or analogue telephone. In VoIP, such a device is used to connect analogue device(s) such as modems or faxes to IP PBX systems. Back to top ^

G

Group Ringing

A group of extensions is called by dialling a number. The group may be set as a ring group, in which case all of the extensions ring at once, or it may be set as a Hunt Group, in which case the system will find a free extension in the group to take the call.

GUI

Graphical user interface. Back to top ^

H

Hosting / Hosted

The process of using a ‘virtual’ space in which the user can place their applications and files.

Hunt Group

A group of users allocated to a particular group (e.g.: sales, accounts) to allow for automated distribution (ACD) of incoming calls. Back to top ^

I

Instant Messaging (IM)

Instant messaging (IM) is a form of real-time communication between two or more people based on typed text. The text is conveyed via devices connected over a network such as a LAN or via the Internet.

IP

Internet Protocol.

IP Telephony

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. Also referred to as VoIP.

ISDN

Integrated Services Digital Network is a type of circuit switched telephone network system designed to allow digital transmission of voice and data over ordinary telephone copper wires, resulting in better quality and higher speeds than available with standard PSTN analogue systems. Typically in the UK, there are two levels of ISDN service: the Basic Rate Interface (BRI) also known as ISDN2 which is intended for the home and small enterprise, and the Primary Rate Interface (PRI) also known as ISDN30, for larger users. ISDN channels can be used flexibly for voice or data and reassigned when necessary to meet special needs (such as videoconferences) and are connected directly to the telephone exchange.

ISDN2

Also known as a BRI, ISDN2 is a 2-channel ISDN Service consisting of 2 x ‘B-channels’ (and 1 x ‘D-channel’) allowing up to 128 Kbps service in total, usually segregated into 2 voice channels.

ISDN30

Also known as PRI. PRI channels are carried on a ‘T-carrier’ (T1) line in the USA, Canada and Japan or on ‘E-carrier’ (E1) line in the UK and other countries. E-carrier ISDN30 is a 30-channel ISDN Service consisting of 30 ‘B-channels’ (and one ‘D-channel’) allowing up to 1.544 Mbps service in total, usually segregated into 30 voice channels. [USA, Canada and Japan ‘T-carrier’ PRI service consists of 23 ‘B-channels’ (and 1 x 64 D-channel) allowing up to 2.048 Mbps service in total, usually segregated into 23 voice channels.]

ISP

Internet Service Provider. A provision for internet connnectivity.

ITSP

Internet Telephony Service Provider (i.e.: a provider of telephony services, such as providing a ‘break out’ conversion of IP calls to normal PSTN calls, via the internet).

IVR

Interactive Voice Response. Technology that allows a caller to interact with the telephone system by responding to a menu of options. Typically this is a voice-based feature that allows callers to be automatically transferred to extensions or departments by dialing digits.  Also known as ‘auto-attendant’. Back to top ^

J

Jitter

Refers to non-uniform delays that can cause voice data packets to arrive and be processed out of sequence. Back to top ^

K

kbps

The speed of data transmission measured as the number of thousands of data bits per second. So 1 kbps is 1,000 bits per second or 125 bytes per second. Back to top ^

L

LAN

Local Area Network.

Landline

A landline or main line is a telephone line which travels through a solid medium, either metal wire or optical fibre. This is distinguished from a mobile cellular line, where the medium used is the airwaves.

Latency

This is any delay associated with the time taken for a packet of information (data or voice) to travel from its source to its destination. In digital systems this is the time delay due to analogue to digital conversions, processing, data transmissions and the processing of protocols.

Layer 2

Layer 2 is the Data Link Layer of the OSI Reference Model. This is the layer which controls access over the physical medium of the network. Two common examples of the Data Link Layer that are well known are ADSL and Ethernet. In Ethernet terms your layer 2 address is your MAC address and it passes ethernet frames on the LAN.

Layer 3

Layer 3 is the Network Layer of the OSI Reference Model. The most well known layer 3 protocol is IP - Internet protocol. The Internet is the largest layer 3 network, and passes traffic via packets.

Layer 4

Layer 4 is the Transport Layer of the OSI Reference Model. This is the “Port” or “Socket” used to transfer specific data types. For example to read this page your computer first had to make a DNS request on port 53 to find the IP address of the server and then had to request the page from our server on port “80″.

Leased Line

A leased line is a symmetric telecommunications line connecting two locations. It is a dedicated non-public line with constant synchronous bandwidth and latency

LES

LAN Extension Services (i.e.: a leased line) Back to top ^

M

MACs

Moves, Adds, Change (and Deletes).

MAC Address

Media Access Control address (MAC address) is a 48 bit address displayed in a hexidecimal number scheme. The first six characters are known as a OUI (organisational unique identifier) or Vendor code, the last 6 characters are unique to that vendor code. This means each 12 character address is globally unique.

Mbps

The speed of data transmission measured as the number of millions of data bits per second.

Modem

A modem is a device that allows you to pass digital information over an analogue medium such as traditional telephone network. The name used tells you how it does this. It “DE-Modulates the digital signal to pass it over an analogue line, the it MOdulates the signal back to a digital signal. Most commonly associated with dial up networking of old, they are also used for ADSL, Cable and Satellite signals.

MOS

Mean opinion score. A measurement of the subjective quality of human speech, represented as a rating index.

MPLS

Multi Protocol Label Switching. MPLS is a protocol used mainly by ISP’s or carriers to transfer data between customers. The protocol works by labelling every packet which contains the data. This allows the packets to be “packet switched” which is faster than the traditional routing of packets. It does have it’s drawbacks due to the increased size of the data due to the label. As a technology what it is most commonly used for is creating a VPN (virtual private network) across a shared ISP’s network as the label stops contamination with other networks. Back to top ^

N

NAT

Network Address Translation. This is generally where a public Internet IP address is translated into a private local network address. This is essential if a group of privately networked computers are sharing the same public Internet connection and the web content is being distributed to them by a router.

Network

A system that transmits any combination of voice, video and /or data between computers. The network includes the network operating system in the client and server machines, the cables connecting them and all supporting hardware in between such as routers and switches.

NTE

Network Termination Equipment. The equipment at the end of a service provider’s communication path. For example, an ISDN30 unit / box on a client premises would be the NTE for a BT ISDN30 service. Similarly, an ADSL router / modem will be the NTE for an ISP’s internet service and a BT socket will be the NTE for a standard PSTN line.

NTP

Network Time Protocol. A protocol used to synchronise computer and device clocks over the Internet. Back to top ^

O

OSI Reference Model

With its background in the 1974 IBM SNA model, the OSI (International Standards Association) reference model is an abstract standard to allow all vendors equipment to be able to communicate / network with each other. It is divided into 7 layers, each providing services to the layer above and below. To transmit data from one machine to another data is passed from the top Application layer down the 7 layers till it finally reaches the Physical layer were is generally a signal on a wire. The benefits this provides in interoperability between applications, software and hardware. Back to top ^

P

Packet

A packet is the fundamental unit of information carriage in all modern computer networks that use packet switching.

Packet Loss

On rare occasions, packet loss will occur in which a portion of the data sent does not arrive at the location intended to receive it. In other words, something goes wrong between the sender and receiver during the call.

Packet Switching

Packet Switching refers to the way that your information will be packaged and then sent over the network. Basically, the pieces are broken up, transmitted separately and put back together on the other end of the transmission. Now more commanly referred to as routing.

More and more now it is also used to refer to layer 3 packet switching technologies such as MPLS.

PBX

A Private Branch eXchange is a telephone exchange that is owned by a private business.

PoE

Power over Ethernet. PoE devices, typically network switches, transmit DC power to the connected devices (e.g.: IP telephone handsets) by carrying power in unused Ethernet network cable wires. PoE enables devices to be installed where there is no AC power outlet and has the advantage that no separate power supply unit or wall power socket is needed. Connected devices that do not make use of PoE may still be connected safely to PoE switches.

POTS

Plain old telephone service. The typical, familiar model of a single phone line and a single phone number.

Presence

Is an indication of the current state of a user, such as ‘Available’, ‘Not Available’, ‘Busy’ or ‘In a Meeting’

PRI

Primary Rate Interface ISDN service. See ISDN30.

PSTN

Public Switched Telephone Network (i.e.: a non-digital standard telephone line).

PWAN

Private Wide Area Network. Generically a PWAN is a marketing term for a VPN WAN using MPLS technology. Like any WAN, it allows communication over long distance, unlike public WAN’s such as the internet it is private. Back to top ^

Q

QoS

Quality of service. The ability of a network to provide different priority to different applications, users, or data flows and to guarantee a certain level of performance to a data flow. The goal of QoS is to provide guarantees on the ability of a network to deliver predictable results. Elements of network performance within the scope of QoS often include availability (uptime), bandwidth (throughput), latency (delay), and error rate. Back to top ^

R

RAID

Redundant Array of Independent Disks. A category of disk drives whereby two or more drives are used in combination for fault tolerance and performance.

Router

A router is a layer 3 device that routes data between networks using IP addresses. Typically, a router is used to route traffic over distance. Back to top ^

S

SBC

Session Border Controller. An interface to a network firewall that facilities the secure hand-off of voice packets from one IP network to another. In an enterprise network a SBC controls the communications session as it crosses the border of the LAN. A session in refers to a call, border refers to a point of demarcation between one part of a network and another.

SDSL

Symmetric Digital Subscriber Line. The main difference between ADSL and SDSL is that SDSL has the same upstream data rate as downstream.

Server

A computer that provides services to other computers, or the software that runs on it. Application server is a server dedicated to running certain software applications. A database server provides database services.

SIP

Session Initiation Protocol. The open standard for controlling IP telephony.

Softphone

Softphone 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.

Splitter

A splitter is a special DSL filter that stops your broadband internet signal interfering with your voice signals (for ADSL).

Switch

In networking terms, a switch is a layer 2 network device that is the central point of connection for computers and other end devices in a computer network. Typically used to transfer data locally via an ethernet frame. Back to top ^

T

T1

A high-bandwidth digital transmission link with a capacity of 1.544 Mbps, used predominantly in North America Canada and Japan. T1 is split into 24 channels each capable of carrying a single voice conversation or data stream.

TAPI

Telephony Application Programming Interface (i.e.: a programming interface that allows Windows client applications to access voice service).

TFTP

Trivial File Transfer Protocol. A light version of FTP without passwords or error checking.

Type of Service

ToS is a layer 3 QoS mechanism for defining type of service. It defines how “important” a packet is and if it should take priority over other data thoughout the whole network. Back to top ^

U

Unified Communications (UC)

Unified Communications is the integration of communication services such as voice calls, unified messaging (e.g.: voicemail, email), instant messaging, faxes, video, web collaboration, conferencing and presence management. Ideally, it allows several technologies / methods of communication to be accessed from a single application with a single, consistent and unified user interface. UC allows a user to communicate via one method but receive it via another: for example, a voice mail message could be accessed via email or via mobile phone. In addition, a user’s ‘presence’ status (knowing whether or not the intended recipient is online and if they are available, in real time) is also a key component of UC as communications can be directed based upon a user’s presence state. UC allows seamless change from one method of communication to another: two users could be engaged in an instant messaging session but then choose to escalate the session to a voice call or video call – all within seconds via a single mouse-click. UC is a mixture of both real-time communications (e.g.: voice or video call) and non real-time communications (e.g.: recorded calls, faxes and voicemails). UC is often referred to as a ‘personal productivity enhancement tool’ that therefore tends to benefit the individual user; whilst such benefits are important, businesses find that they can achieve an even greater impact by using UC to transform business processes. Finally, UC is sometimes incorrectly referred to as the method of placing both voice and data communications over a single physical cable / network but, put simply, UC is a way of integrating communication systems that may already be in use, making those systems work together in a simple and effective way.

UPS

Uninterruptable Power Supply. Back to top ^

V

Value Added Reseller (VAR)

Value Added Reseller. Also called “VAR’s”, or simply “resellers”. Retailers / manufacturers typically add little value to a product, if any at all, and often only channel-sell to VAR’s instead of directly to businesses in order for the VAR to add the required value that they cannot or do not wish to do themselves. The ‘value add’ can come from a wide range of professional services such as consultancy, requirements capture, implementation, customisation, training and support. The VoIP industry is ‘channel based’ and relies heavily on VAR’s.

Voicemail

A voicemail system typically provides a central “answering machine” for users of a telephone system. The user diverts his calls to the voicemail system, which will play a personalised message to a caller and allow him to leave a message for the extension user. Most voicemail systems also provide options for routing callers to departments or extensions and for giving out information to callers.

VLAN

Virtual Local Area Network is the separation of different devices on a layer 2 local area network into different and separate networks. Typically used to increase performance and it removes large broadcast domains. As such you need a router to pass traffic between VLAN’s.

VoIP

Voice over Internet Protocol. 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. Also referred to as IP Telephony.

VPN

Virtual Private Network (i.e.: a communications network ‘tunnelled through’ another network, usually dedicated for a specific network use where data is segregated for different user communities over an underlying network with strong security features). Back to top ^

W

WAN

Wide Area Network. A network that spans a large geographic area.

WES

Wholesale Extension Services (i.e.: a leased line). WES provides a high-speed, permanent, point-to-point circuit, offering secure and reliable bandwidth nationally for the transmission of data, voice and video.

WEES

Wholesale End To End Ethernet Service. Back to top ^

X

xDSL

Digital Subscriber Line. This is a family of technologies that enables copper telephone lines to carry data-streams at high-speeds. Also known as xDSL, the ‘x’ is simply a placeholder which can be replaced to denote different DSL technologies, such as ADSL and VDSL. Back to top ^