Terms Often Associated with ATM Technology Or Networking

Access Concentrator
Also known as an Access Device. Literally the gateway to the ATM network. Provides access between the multiple hardware and applications "behind" the device.

ATM
Asynchronous transfer mode. A telecommunications technology to transmit data, based on standards recognized worldwide. Allows users to exchange voice, data and video signals with a single connection to a network.

BPs (Bits-Per-Second)
A measurement of how fast data is moved from one place to another. A 28.8 Kbps (kilobits per sec.) modem can move 28,800 bits per second.

Bandwidth
How much data you can send through a connection. Measured in bits-per-second or BPs.

Bit
The smallest unit of computerized data. Bandwidth is usually measured in bits-per-second. Transmitted as either "1. s" or "zeros" over digital networks. A full page of English text is about 16,000 bits.

Bridge
The interconnection process or device which typically allows three or more users to hold a video or audio conference at the same time. Also known as an MCU (Multipoint Control Unit).

Broadband
A service or network capable of supporting a wide range of multiple transmissions (video, data or audio) at the same time.

Byte
8 bits.

Cell
A unit of data (53-bytes) used in ATM technology for transporting information.

CODEC
A coder/decoder used to change a signal from analog to digital or from digital to analog.

CSU/DSU
Channel Service Unit/ Data Service Unit. A device that is placed at the end of a data circuit. Typically connected to the router. Used in transmitting data.

DS-3
A very, very high speed network line, operating at 44.73 Mbps (megabits per sec.).

E-mail
Messages, usually text, sent from one person to another via computer.

Hub
A device used to connect several computers together, and to networks.

IP Address
A unique series of numbers assigned to each system on a network, including computers. Required before a computer can access the Internet or send and receive e-mail.

Internet
(upper case I) Refers to the worldwide network or Web of computers.

intranet
A private network that uses the same kinds of software that you would find on the Internet or the ATM network, but only for internal use and internal users.

LAN
Local Area Network. A data network intended to serve a small area, such as a building.

LANE
Local Area Network Emulation. ATM devices communicate by emulating a LAN.

MCU (Multipoint Control Unit)
Also known as a bridge. Typically, an interconnection device that allows three or more users to hold a videoconference at the same time.

MPEG (Motion Pictures Expert Group)
A worldwide standard for sending video. MPEG 1 is a business quality standard commonly used in videoconferencing. MPEG 2 is a standard more like today's television broadcasting quality.

Multimedia Computer
A computer capable of supporting video and audio for one-way or interactive videoconferencing, or receiving and displaying video on the desktop.

Network
A data communications system that interconnects computer systems at various sites. May be composed of any combination of LANs and WANS.

OC-3 (or DS-3)
A connection capable of carrying data at 155.52 Mbps.

Quality of Service or QoS
A measure of service provided to users on the ATM network. A guarantee that data or video can be sent between devices on the network.

TCP/IP
(Transmission Control Protocol and Internet Protocol) Software required before a computer can communicate on the Internet.

Router
A device used to forward data between networks. This special-purpose computer (or software package) constantly examines the destination addresses of the information passing through them and decides which route to send them on.

Server
A computer that provides a specific kind of service to other computers. A server can link computers to the Internet, provide e-mail or provide specific applications like the IAS application from the Tax Department.

T-1 (or DS-1)
A connection capable of carrying data at 1,544,000 bits-per-second or 1.5Mbps.

T-3 (or DS-3)
A connection capable of carrying data at 45,000,000 bits-per-second or 45Mbps.

UNI
User-Network Interface. A customized device that provides access for various equipment and applications on ATM networks.

Videocache
A device which stores video in digital form and is accessed over the network. Stores from three to 300 hours of digitized video content. Up to 55 different users can access the same video content simultaneously. One unit on a WAN could serve a large number of users.

Videocasting
The transmission of digital video information to multiple users on the network at the same time, on one or more channels.

Videoconferencing
The ability to "dial" another videoconferencing device or host, including multimedia computers, for face to face, interactive communications.

Video On Demand or VOD
Ability to access video anywhere on the network, much like accessing a file on your computer. VOD can be built into many applications, including Web documents and Microsoft PowerPoint and Word documents. In this manner, users simply "point and click" to access and begin a video.

Video Switch or Multimedia Device
An ATM device that literally switches video input and output. A single switch can connect videoconferencing equipment to an ATM network.

WAN
Wide Area Network. A circuit that connects sites that are miles apart.