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.
BOCs

Bell Operating Companies.?Grouped under the seven Regional BOCs.
Bps

Bits per second.?The number of binary digits transmitted per second. This transmission particularly applies to a modem. Common modems transmit at either 14.4 Kbps (14,400 bps) or 28.8 Kbps (28,000 bps), but newer modems are capable of 33.6 Kbps and 56Kbps, and in some cases, transmission speed may extend to 128 Kbps.
Brightness

The perception of luminance by the human eye. Although many use luminance and brightness interchangeably, they are not exact synonyms.
Broadband

A telecommunications medium composed of a bandwidth high enough to transmit high-quality voice transmissions and a wide band of frequency. Television, microwave, and satellite transmission are all example of this medium.?Browser.?Also known as a Web browser. Any program that permits access and searches on the World Wide Web.
Byte

A string or cluster of eight bits to represent a character.
CAD

Computer-aided Design.
CATV

Cable Television.?A system of transmission that distributes broadcast television signals and other various services via a coaxial cable.
CCD

Charge-coupled Device.?A light-sensitive device that converts light information into electronic information via sensor that collect light as a buildup of electrical charge. The signal that results from this conversion can be converted into computer code and then used to form an image. This device is commonly used in television cameras and image scanners.
CCITT

Consultative Committee on International Telephone and Telegraph.?Currently, the International Telecommunications Union Consultative Committee for Telecommunications (ITU-T). An international agency responsible for developing standards for telecommunications, as well as FAX and video coder-decoder (CODEC) devices.
CD-ROM

Compact Disk, Read Only Memory.?A device used for storing large amounts of information, the equivalent of about 220,000 pages of text.
CDC

Center for Disease Control
CDS

Clinical Decision Support.?Information regarding a patient, his or her health problems, and alternative tests/treatments used to aid a clinician in diagnosis and treatment. Also referred to as Clinical Decision Support Systems (CDSS).
CEN

European Technical Committee for Normalization.?An international agency responsible for setting standards in health care informatics.
Channel

A radio frequency assignment designed depending on the frequency band being used and the geographic location of the sending/receiving sites.
CHIN

Community Health Information Network.?A popular system of communication created for common use by health professionals, patients and the community. This system fuses hospital information systems (HIS) with medical databases, community health information, and on-line computer services.
Circuit Switched Network

Also may be called line switching and dial-up service, this network temporarily links multiple channels between multiple points that permits the user to exclusive use of an open channel to exchange information.
Clinical Information System

Relating exclusively to the information regarding the care of a patient, rather than administrative data, this hospital-based information system is designed to collect and organize data.
Closed

Refers to a type of mailing list that allows only members of that mailing list to send messages to it. Distinctive from 'open' or 'moderated'.
CME

Continuing Medical Education.
CMHCs

Community Mental Health Centers.
Co-processor

A device within a computer to which specific processing operations are assigned, like mathematical computation or video display. This device accelerates processing speed significantly.
Coaxial Cable

A single or dual transmission wire covered by an insulating layer, a shielding layer, and an outer jacket. Because it contains a high bandwidth, this cable may be a broadband carrier with the ability to transmit data, voice, and video.
CODEC

Coder-Decoder.?A device that converts a digital signal to an analog signal at one end of transmission, and back again to a digital signal at the opposing end.
COM port

Serial port for connecting a cable to an IBM PC-compatible computer, usually, but not exclusively for data communications. They are referred to by the operating system as COM1, COM2, COM3, etc.
Common Carrier

A telecommunications company, charging published and nondiscriminatory rates and regulated by the government, which offers communications relay services to the general public by means of shared circuits.
Communication Multiplexer

An instrument that permits data from multiple, lower speed communication lines to share a single higher speed communication path.
Compatibility

Refers to the ability of two pieces of hardware (a personal computer and a printer, for example) to work together. Standards, published specifications of procedures, equipment interfaces, and data formats are essential to decreasing and possibly eventually extinguishing incompatibility.
Compressed Video

Video images that have been processed to reduce the amount of bandwidth adequate for capturing the necessary information so that the information can be sent over a telephone network.
Compression Ratio

The ration of the number of bits in an original image to the number in a compressed version of that image. For example, a compression ratio of 3:1 would signify a compressed image with a third of the number of bits of the original image.
Computed Radiography (CR)

A system of creating digital radiographic images that utilizes a storage phosphor plate (instead of film) in a cassette. Once the plate is exposed, a laser beam scans it to produce the digital data which are then translated to an image.