Telecommunications and Data Glossary

A

ACD – Automatic call distribution is a means of distributing incoming calls to a group of extensions on a first come, first served basis.
ADCPM – A CCITT (The International Telegraph and Telephone Consultative Committee) recommendation for compressing voice signals into 32K of bandwidth.
Address – A unique identifier used to distinguish between nodes/devices on a network.
Alternate Routing – A safety feature within the routing protocol that allows a router to re-route a data path to an alternate path on failure of the first.
Analog – A traditional method of transmitting information along the phone lines.
API – Application Program Interface. A set of calling coventions defining how a service is invoked through a software package.
APPLE TALK - An Apple Computer networking system that operates over STP wire at 230 Kbps.
APPLICATION LAYER-The top-most layer in the OSI Reference Model providing such communication services as electronic mail and file transfer.
ATM – (Asynchronous Transfer Mode) The CCITT standard for cell relay where information such as voice, video and data is conveyed in fixed size cells.
Automated Attendant – Automatic attendants are electronic switchboard operators, giving caller a series of options which they select from the keypad on their switchboard
Authentication – The mechanism whereby an SNMP agent verifies the authenticity

B

Backbone – The primary connectivity mechanism of a hierarchical distributed system. All systems which have connectivity to an intermediate system on the backbone are assured of connectivity to each other.This does not prevent systems from setting up private arrangements with each other to bypass the backbone for reasons of cost, performance or security.
Back Up Server – Software or hardware that copies files so that there are always two current copies of each file. Also known as a shadow server.
Bandwidth-on-demand – The ability to add and drop B-channels based on the sending of threshold data levels. Specifically, it is the ability to raise a call over a second B-channel when the first B-channel becomes saturated and to drop the call when data rates decline. Also called Dynamic Bandwidth Allocation.
BRI (2B+D) - Basic Rate Interface. Access to the public switched telephone network comprising of two 64 kbit channels and 16 kbit signaling.
Bridge – A LAN interconnection device used to link two or more local or remote LAN’s.
Broadcast – A packet delivery system where a copy of a given packet is given to all hosts attached to the network.
Bus Topology - A type of network in which all the devices are connected in a line to a single cable. A bus network has two distinct ends. All devices attached to a bus network have equal access to it and can see all the messages that are put onto the network.

C

Cache – A dedicated portion of a computer’s Random Access memory (RAM) that stores the last items that were retrieved from a disk. In certain applications the cache can significantly improve performance.
Call Centers – A call centre can be a specific department or part of an organisation where staff intensively use the telephone. Call centre technology is a way of organising calls so that customers can be dealt with more effectively. These are mainly used where large numbers of the general public have to be dealt with.
Call forwarding – a user can arrange to have calls forwarded to one or more designated extensions.
Call Logging – Call logging is used to record details such as the numbers dialed from each extension, call duration and date the call was made. This is useful to manage calls. Call information can normally be down loaded to a printer.
Call Pick Up – enables an extension user to answer a call on another extension
Call Waiting – an indication e.g. a bleep that a call is waiting
Category 5 Cable – This UTP cable is the preferred standard to flood wire a building. It is suitable for voice services as well as data services up to 100Mbps.
CHAP- Challenge Handshake Authentication Protocol – a standard security protocol.
CIR – (Committed Information Rate) the speed at which a Frame Relay network will transmit information between locations.
CLI – This feature allows you to see the number of the person who has called you.
CLIR – This puts a block on CLI and allows callers to prevent the called party from gathering information on them.
Client- Server Model - A common way to describe network services and the model user processes (programs) of those services. Examples include the name-server/name –resolver paradigm of the DNS and file –server/file-client relationships such as NFS and diskless hosts.
Conference Call – This allows a telephone conference to be set up between more than two parties
Connectionless - The model of interconnection in which communication takes place without first establishing a connection. Sometimes (imprecisely) called datagram. Examples-LANs,Internet IP and OSI CLNP,UDP,ordinary postcards.
Connection-orientated - The model of interconnection in which communication proceeds through three well-defined phases, connection establishment, data transfer, connection release. Examples- X.25,Internet,TCP and OSI TP4,ordinary telephone calls.
CSMA/CD - Carrier Sense Multiple Access with Collision Detector. The access method used by local area networking technologies such as Ethernet.

D

DASS II - A telecommunications protocol for access to the public switched network over 2 Mbit lines.
Data Compression – Utilising an algorithm data is compressed so that more information can be transmitted in a given time period.
Data Link Layer - The OSI layer that is responsible for data transfer across a single physical connection or series of bridged connections between two Network entities.
DDI – Direct Dialing in allows callers to ring specific extensions instead of going through a switchboard.
Digital – This is a method of transmitting information down the phone lines. It uses binary code and has a number of advantages over analogue technology. It is highly resistant to electro-magnetic interference, nearly impossible to bug, and allows the integration of voice and data over telecommunication lines.
DISA – Direct Inward System Access is a way of accessing a specific extension. Callers dial in, hear a dialing tone and then dial the specific extension number they require.
Domain - In the internet,a part of the naming hierarchy. Synatically,an Internet domain name consists of a sequence of names (labels) separated by periods (dots) e.g. "sdxplc.com ". In OSI, "domain" is generally used as an administrative partition of a complex distributed system,as in MHS Private Management Domain (PRMD), and Directly Managed Domain(DMD).
DPNSS- Digital Private Network Signaling System - A telecommunications protocol for interconnecting PBX’S over 2 Mbit leased lines.
DTE - Data terminal Equipment. The user equipment connected to a network DCE. Example , a terminal, computer.

E


Ethernet - The most widely used LAN transmission network. Based on a bus network topology, it runs at a maximum 10Mbit/s – in practice far less- and adopts CSMA/CD techniques operating over conventional coax cable, thin wire coax cable and unshielded twisted pair cabling.
Exchange Lines – Exchange lines link the telephone system to the public telephone network.
Exclusive Hold – Exclusive hold is a key system feature which allows you to put a call on hold exclusively. This prevents any other extension from advertently picking up your call instead of one they put on hold.

F

Firewall - A system or group of systems that enforces an access control policy between an organisation’s network and the Internet for purposes of security.
Frame Relay - A packet –switching wide-area technology for interconnecting LANs at high speeds.
Full Duplex - A channel capable of transmitting in both directions at the same time.

G

Group hunting – some systems can be programmed to try any number of extensions in turn until one is found to be free to take a call

H

Hands free operation – the telephone acts as an intercom and is used without the need to remove the handset.
HTML - Hypertext Mark-up Language. Simple hypertext document formatting language that uses tags to indicate how a given part of a document should be interpreted by a viewing application,such as a Web browser.

I

Internet - A collection of networks interconnected by a set of routers which allow them to function as a single large virtual network.
Internet Address - A 32bit address assigned to hosts using TCP/IP. See dotted decimal notation.IP - Internet Protocol. The network layer protocol for the Internet protocol suite.
IP Address - The 32bit address assigned to hosts that want to participate in a TCP/IP Internet.
IPX (Internetwork Packet Exchange, Network Protocol - LAN protocol developed by Novell for Netware.
ISDN (Integrated Services Digital Network) - An emerging technology which is beginning to be offered by the telephone carriers of the world. ISDN combines voice and digital network services in a single medium making it possible to offer customers digital data services as well as voice connections through a single "wire". The standards that define ISDN are specified by CCITT.
ISP – Internet Service Provider – An ISP is a company that provides individuals and other companies access to the Internet.
IVR – Interactive voice response – a voice computer, suing a prerecorded voice to offer information or moving a call around an automatic distributor to direct it to an operator specialised in a particular subject.

J

Jabber – To send random data continuously on an Ethernet LAN as a result of a faulty adapter card.

K

Kilostream – A registered trade mark denoting British Telecoms synchronous point to point network service. Speeds range from 2.4K to 1.92Meg.

L

LANs – Local Area Networks (LANs) link computers together so they can share files, software, hard disks and peripherals such as printers.
Last Number redial – This allows you to call the last number you dialed again by pressing a single dedicated key.
Leased Line – A service provided by a PTT, which gives a permanent connection to another physical point.
Led/LCD Displays – Found on the more sophisticated key stations and feature phones, on both key systems and PBXs, LED/LCD displays can show the number you have dialed and the number of an internal calling party.

M

Mail Gateway - A machine that connects two or more electronic mail systems( especially dissimilar mail systems on two different networks) and transfers messages between them. Sometimes, the mapping and translation can be quite complex and generally it requires a store-and-forward scheme whereby the message is received from one system completely before it is transmitted to the next system after suitable translations.
Modem - A device named from an amalgam of the words modulator and demodulator. A modem will modulate an outgoing, binary bit stream on to an analogue carrier and demodulate an incoming binary bit stream from an analogue carrier.
Multimedia – A generic description of a device that will cope with differing media types i.e. Video, Voice and Data.
Multiplexer - A device that can send several signals over a single line. They are then separated by a similar device at the other end of the link.

N

Netware - LAN NOS developed by Novell. There are two main product lines-NetWare 2.X (latest version 2.2.) designed to run on an Intel 80286 platform and above and Netware 3.X (latest version 3.11) designed to run on an Intel 80386 platform and above.
Network Interface card – A card that fits into the computer equipment to facilitate connection to the network.
Node – devices connected to a network that provide services.

O

OFTEL – The Office of Telecommunications (OFTEL) is a non-ministerial government department with responsibility for regulating the telephony market in the UK.
Optical Fibre Cabling – This is used for the trunk networks operated by the telephone operators

P

PAP- Password Authentication Protocol.
PBX’s – (private automatic branch exchanges) is linked to PSTN and routes calls internally.
Ports– Telephone systems either give their size in terms of the maximum number of exchange and extension lines available or in terms of the number of "ports" (access points to external lines or internal terminals) they have.
PPP – Point to point tunneling protocol used for communication between two devices usually over a serial line
PRI - Primary Rate Interface. Access to the public switched telephone network at 2Mbits.
Protocol - A formal description of messages to be exchanged and rules to be followed for two or more systems to exchange information.
PSTN – (Public Switched Telephone Network) the standard telephone network

R

RJ45 – A cable connector predominantly used to connect UTP cable to PC.
Router - A system responsible for making decisions about which of several paths network ( or Internet) traffic will follow. To do this it uses a routing protocol to gain information about the networks and algorithms to choose the best route based on several criteria known as "routing metrics". In OSI terminology, a router is a Network layer Intermediate system. See Gateway,Bridge and Repeater.
Routing Table - Information stored within a router that contains network path and status information. It is used to select the most appropriate route to forward the information along.

S

Server – A node within a LAN that grants and controls access by other nodes to its facilities.
SQL - Structured Query Language. The International standard language for defining and accessing relational databases.
Statistical Multiplexing – A form of multiplexing that allows full utilisation of the bandwidth by any attached device as and when it is required.

T

Token Ring - A 4/16 Mbit/s LAN architecture which uses a token passing access method to allow nodes on the network to transmit data. Defined in IEEE 802.5 with a ring architecture, a special data packed,called a token, is passed continuously from node to node.

V

Videoconferencing – Using a small camera and a PC to encode and display the video and voice information, a connection can be made between two users to hold meetings.
Virus – A small program that copies itself from one machine to another. The purpose of these programs is to damage files

W

WANS – WANS or Wide Area Networks connect geographically remote LANs.
WWW – A generic term for the ‘Internet.’

X

X.21 - Recommendations developed by Comite Consultatif Internationale de Telegraphique et Telephonique (CCITT) that define a protocol for communication between user devices and a circuit-switched network.