Glossary

Compiled by Marlene M. Maheu, Ph.D. and Ace Allen, M.D.
ADSL

Asymmetrical Digital Subscriber Line.?Refers to a pair of modems connected by a copper line that yields asymmetrical transmission of data.
Amplifier

Electronic devices that strengthen a signal as it passes along a communications channel
Analog Signal

A wave shaped electrical symbol, which continuously changes with respect to size and shape depending on the information source. Differences in volume, voice and pitch are a result of signal variations.
ANSI

American National Standards Institute
Architecture

The selection, design, and interconnection of the hardware of a computer system.
Archiving

A method of transferring information created during operations into a more permanent form. Systems vary from manual backups, through periodic transfer to audio cassettes, to real-tune storage onto WORM (Write Once Read Many) disks.
ARPA

Advanced Research Projects Agency.?Governed under the Department of Defense, this agency is involved with the use of telemedicine, its development, and continuing research. The ARPA is responsible for establishing the network, which later became known as the Internet.
ARPANET

Advanced Research Projects Agency Network.
Asynchronous Communication

Refers to systems of communication where there is a lapse in time from when a message is sent and when it is received
ATLS

Advanced Trauma Life Support.?The basic skills for resuscitation employed by emergency care workers
ATM

Asynchronous Transfer Mode.?A way of transmission where a start signal precedes individual characters and one or more stop signals follow it. Due to this start/stop system, delays may occur between characters. Also denotes the complete system of protocols and equipment associated with cell based communications network. These networks have the ability to transmit voice, data, and video traffic simultaneously using a statistical multiplexing scheme. This type of switching is expected to bridge the gap between packet and circuit switching. ATM uses packets referred to as cells that are designed to switch cells so rapidly that there is no perceptible delay.
Audio-teleconferencing

Two way communications between multiple people at various locations.
Authentication

A method of verifying the identity of the person sending or receiving information by use of passwords, keys and other automated identifiers
Automated Data Collection

The direct transmission of physiological information from monitoring devices to either a bedside display system or a computer-based patient record.
B-CDMA

Broadband Code Division Multiple Access.?A form of wireless technology where digital information is sent over communication networks
Backbone Network

A high-speed, high capacity transmission facility created to interconnect lower speed distribution channels from smaller branches of the computer or telecommunication network.
Bandwidth

Measures the ability of a communications channel to carry information. The capacity of information increases relative to a higher megahertz (cycles per second) in an analog transmission, and in megabits/second (Mbps) for digital transmission
Baud

A unit of digital transmission that indicates the speed of information flow. The rate indicates the number of events able to be processed in one second and is expressed as bits per second (bps). The baud rate is the standard unit of measure for data transmission capability. Typical rates are 1200, 2400, 9600, and 14,400 baud.
BBS

Bulletin Board Service.?A computer service that allows users in an isolated location to access a central host computer through a computer in order to read and send electronic messages.
Bit

Binary digit. This is the smallest piece of digital information that a computer handles. This system limits this information to an 'on' or 'off', represented by a 0 or 1. All characters, numbers and symbols are translated into electronic strings of bits.