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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Computer Conferencing.
Communications within groups through
computers, or the use of shared computer files, remote terminal
equipment, and telecommunications channels for two-way
communication.
Conference.
Multiple public messages found on a system,
usually specific to a particular topic and sometimes moderated by
a conference host who leads the discussion. Also called "Folder,"
"SIG" (Special Interest Group), or "Echo." Very much like the
newsgroups on the Internet.
Connectivity.
The ability to send and receive information
between two locations, devices, or business services.
CPR.
Computerize Patient Record.
A record, in electronic form,
that is comprised of individual patient information that resides
in a system capable of providing access to complete and accurate
patient data, alerts, reminders, clinical decision support
systems, links to medical knowledge, and other aids.
CPRI.
Computer-based Patient Record Institute, Inc.
An
independent institute that develops and recommends standards for
computerized patients records.
CPU.
Central Processing Unit.
The device in a computer that
executes directions in software programs and performs
calculations and other operations.
CRT.
Cathode Ray Tube.
The monitor or other means of
displaying data in a computer system.
Crawlers.
The software used to index the World Wide Web. Also
referred to as "robots" and "spiders."
Data Compression.
Method to reduce sheer volume of data by
more efficient encoding practices, thereby reducing image
processing, transmission times, bandwidth requirements, and
storage space requirements. Some compression techniques result in
the loss of some information, which may or may not be clinically
important.
Data Repository.
The element of an information system that
accepts, files, and stores data from various sources.
DAX.
Digital Exchange.
A computerized digital cross connection
that permits specific channels from high capacity lines to split
out separately so that they may be directed elsewhere.
DBS.
Direct Broadcast Satellite.
A satellite designed with
adequate power so that inexpensive earth stations, or downlinks,
may by used for direct residential or business reception.
DDS.
Digital Data System.
A system for transmitting telephone
traffic in digital format between major switching hubs. This
system allows digital transmission of voice and data as a
component of the analog telephone system (POTS).
Dedicated Line.
A permanent telephone line reserved
exclusively for one patient, accessible all hours of the day.
These lines usually offer better quality than standard telephone
lines, but may not significantly augment the performance of data
communications. May also be known as "leased," or "private"
lines.
DICOM.
Digital Imaging and Communications in Medicine.
A set
of protocols describing how radiology images are identified and
formatted that is vendor-independent and developed by the
American College of Radiology and the National Electronic
Manufacturers Association. The standard emphasizes point-to point
connection of digital medical imaging devices. DICOM 3.0 is the
current version.
Digital.
Used in both electronic and light-based systems,
these signals transmit audio, video, and data as bits. Digital
technology allows communications signals to be compressed for
transmissions that are more efficient.
Digital Camera.
An image producing lens system made up of one
or more light-sensitive integrated circuits, a myriad of light
sensitive elements, and circuits for timing, nonlinear
amplification, and encoding color.
Digital Image.
An image formed by independent pixels, each of
which is characterized by a digitally represented luminance
level. For example, a popular screen size for digital images is a
1024 by 1024 matrix of pixels x 8 bits, representing 256
luminance levels.
Digital Signal.
An electrical signal in the form of discrete
voltage pulses. These signals transmit audio, video, and data as
bits, which are either on or off, differing from analog signals,
which are continuously varying. Communications signals may be
compressed using digital technology, allowing efficient and
reliable transmission rotes.
Digitize.
The process by which analog, or continuous,
information is transformed into digital, or discrete,
information. Because most computers are only capable of
processing digital information and visual information is
inherently in analog format, this process is essential in
computer imaging applications.
Direct Capture.
A procedure by which image data are formed
directly from the original source allowing a high quality image
reproduction. In this process, images created from image files
are identical to the original, regardless of the device used to
capture them, such as a CT or an MRI. In direct video capture,
the video signal is digitized from the display, which creates a
higher quality image and is more efficient than acquisition
through scanning.
Dish.
An antenna shaped like a parabola that is the essential
component of a satellite earth station, or downlink.
Domain.
The last two parts of an e-mail address or an URL
signifying an organizations name on the Internet. For example,
"aol.com" refers to America OnLine.
Download.
The process of transferring files or software from
another computer to your computer.
Dpi.
Dots per inch.
The number of dots or pixels per inch used
in film resolution. In conventional radiography resolution is
given in line pairs per millimeter (lp/mm).
DS0, DS1, DS2.
Digital telecommunications channels.
These
channels are capable of transmitting high volume voice, data or
compressed video signals. DS1 and DS3 are also known as T1 and T3
carriers. Transmission rates are 64 Kbps for DS0, 1.544 Mbps for
DS1, and 45 Mbps for DS3.
Duplex.
A transmission system permitting data to be
transmitted in both directions simultaneously.
Dynamic Range.
The characteristic of a communications or
imaging system to reproduce or transmit various brightness
levels.
Earth Station.
The ground equipment essential for receiving
and/or transmitting satellite telecommunications signals.
EDI.
Electronic Data Interchange.
Refers to any transmission
of information without paper or human intervention between two
devices or application, using a standard data format.
Email.
An electronic system of transmitting messages through a
computer system. Data can be transmitting to anywhere in the
world for the price of a local telephone call. An email address
is typically made up of a part of your name (your account name),
the "at" sign (@), and your domain name.
Encryption.
A system of encoding data on a Web page or e-mail
where the information can only be retrieved and decoded by the
person or computer system authorized to access it. Often used on
the web to protect financial data.
Ethernet.
A communications protocol that utilizes various
types of cable at a rate of 10 Mbps.
Equal Access.
The ability to choose between various long
distance carriers. However, in more remote areas, some local
exchange carriers are still serviced by only one long distance
carrier.
FAQ.
Frequently Asked Questions.
A file developed for many
public discussion groups that consist of popular questions and
their answers.
Fax.
Facsimile.
A device which enables a user to
electronically transmit and reproduces documents over telephone
lines.
FDDI.
Fiber Distributed Data Interface.
A high-speed fiber
optic network containing a state-of-the art bandwidth.
Fiber Optic Cable.
Cable that is insulated, flexible and
consists of a glass core that relies on light sources rather than
electricity to transmit audio, video, and data signals. This
system permits high capacity transmission at extreme speeds,
sometimes billions of bits per second, with very low error
rates.
Film Alternator.
A device powered by a motor that displays
multiple films for interpretation and moves them under the
control of an operator. This device may be thought of as multiple
banks moving view boxes.
Film Digitizer.
An instrument that permits scanning of
existing static images so that the images may be stored,
manipulated, or transmitted in digital form.
Firewall.
Computer hardware and software designed to prevent
unauthorized communications between an institution's computer
network and external networks.
Flame.
A negatively charged message, often contemptuous and
sometimes abusive, that is sent responding to another message in
a public discussion forum online. Sending a flame, or "flaming"
is highly discouraged.
Footprint.
The geographic range on the earth beneath a
satellite that is in the scope to receive that satellites
information.
Frame.
Also known as "framed." A Web sight with this
characteristic is one that divides your Web browser's screen into
smaller sections. Each area displays different data, usually to
help the user navigate the Web sight, or to display
advertisements.
Frame Relay.
Created to improve the rate of data transfer
compared to previous transmission protocols, frame relay is a
streamlined process of sending and acknowledging transmitted
packets of data.
Freeze Frame.
One way to transmit still images over regular
telephone lines. A single image is transmitted every 8 to 30
seconds. This method may also be known as slow scan.
Frequency.
The rate at which an electromagnetic signal
alternates, denoted in Hertz.
FTP.
File transfer protocol.
The typical process for
transferring files over the Internet or the software program that
uses this procedure. Using this program, the user is permitted to
connect to another computer online to transfer files to his/her
desktop computer using a GET command. An "anonymous" ftp is
usually allowed, where the user would enter "anonymous" as the
login name, and his/her e-mail address as the password, enabling
the user to access a limited number of public directories where
files can be retrieved.
Full duplex.
A channel used for communication that is capable
of both transmitting and receiving in two directions at the same
time. A standard telephone line is one example of this because
both parties can simultaneously speak while listening to the
voice on the opposing end.
Full-motion Video.
A standard video signal, conventionally
requiring 6 Mhz an analog format and 90 Mbps when digitally
encoded, that is able to be transmitted by a variety of ways
including television broadcast, microwave, fiber optics, and
satellite.
Gateway.
A computer used to provide translations between
different types of standards. Generally refers to computers that
translate complex protocol suites; for example, different E-mail
messaging systems. Currently, it has been used to describe a
"door" from a private data network to the Internet.
Gbps.
Gigabits per second.
A measure of bandwidth and rate of
data flow in digital transmission.
Gb.
Gigabyte.
A measure of the storage capacity and memory of
a computer. One gigabyte is equivalent to 1.074 billion bytes or
1,000 Mb. Usually used to express a data transfer rate, (1
gigabit/second=1 Gbps). The bandwidth of optical fiber is often
in the gigabit or billion-bits-per second range.
Ghz.
Gigahertz.
One billion cycles per second. It measures
analog signal transmission.
GIF.
Graphical Interface Format.
A typical graphics or image
file commonly used on the Web that is most effective when the
graphic or image is not a photograph.
Geostationary Orbit.
Refers to the orbit of a satellite whose
location relative to the earth's surface is constant so it seems
to hover over one sport on the earth's equator.
Gopher.
A predecessor to the World Wide Web. A method of
storing and retrieving text and software files on the Internet.
More user friendly than ftp, but less so than the Web.
Gray Scale.
Refers to the quantity of various tones or levels
of gray than can be stored and displayed by a computer system.
The number of gray levels, or gray scale, is directly related to
the number of bits used in each pixel, with the number of gray
levels doubling for each added bit. For example, there are 64
gray levels in a 6 bits system, 128 gray levels for 7 bits, 256
gray levels for 8 bits, and so forth.
Gray-scale Monitor.
A visual display with varying shades of
gray, extending up to thousands, making it capable of displaying
an image. May also be known as a monochrome monitor.
GUI.
Graphical User Interface.
A method of controlling
computers using graphic images or icons, to which the user
accesses using a mouse.
Guide.
A list of online resources, usually Web sites, which
may be generalized or specific, compiled by human editors. This
index is generally less comprehensive than search engines, but
often more specific. May also be known as a "search" or "subject
guide."
Half Duplex.
A channel of communication which is capable of
both transmitting and receiving information, but only in one
direction at a time.
Hard Drive.
The storage device within a computer used to save
data, files, and programs.
Hardware.
Used to refer to all the tangible equipment related
to information technology, including the computers, peripheral
devices, such as printers, disks, and scanners, and the cables,
switches, and other components of the telecommunications
infrastructure that binds everything together.
Hard Wired.
Refers to the permanent connection of two devices
by a communications link.
HCII.
Health Care Information Infrastructure.
A subset of the
National Information Infrastructure.
HDTV.
High-definition television.
A television system with
1125 lines of horizontal resolution, with the ability of creating
high quality video images.
Hertz.
A unit of frequency equivalent to one cycle per
second.
HIS.
Hospital Information System.
Used to store and retrieve
patient information, this integrated computer-based system may
include or be linked to laboratory and radiology information
systems (LIS and RIS).
HISPP.
Health Care Information Standards Planning Panel.
Established by the ANSI, this panel coordinates the evolution of
standards using standard-setting organizations in health
care.
Hit.
Recorded each time a Web browser display a page, a hit
refers to a single access of a Web page. It is common for a
user's homepage to display the number of hits it has received,
and this number is used by Webmasters to determine the popularity
of any given Website and thus how much attention it should
receive.
HL7.
Health Level 7 Data Communications Protocol.
Used at the
applications level, this communication protocol outlines the
guides to transmitting health-related information. Usually used
within a single institution, HL7 allows the synthesis of various
applications, such as bedside terminals, radiological imaging
stations, hospital census, order entries, and patient accounting,
into one system.
HMO.
Health Maintenance Organization.
Home page or Homepage.
In a hierarchical collection of linked
HTML documents, this term refers to the top-level hypertext
document. It is typically the document implied in a WWW site's
address.
HPCC.
High Performance Computing and Communications.
A program
of research coordinated by the Federal Government focused on
research and development, created to expedite the introduction
and use of the next generation of high performance computer
systems.
HTML.
Hypertext Markup Language.
The guides to publishing used
on WWW pages. It defines the events when the user clicks on a
hypertext link embedded in the page. HTML is a publishing
standard, not a programming language. HTML document comprise the
core of a Web site, and can be identified by an .html or .htm
suffix.
HTTP.
Hypertext Transport Protocol.
The standard by which the
World Wide Web operates.
Hypertext Link.
Sometimes known simply as a "link". This
visual aid, usually signified by highlighting, underlining or
graphics, instructs the computer to display a specific Web
document. This system permits users to move easily within a Web
site or across Web sites residing on different computers. A "bad"
link, which refers to one that does not work properly, will
display an error message rather than the Web page the user was
attempting to visit. Bad links are generally caused because a Web
site has changed location without leaving a forwarding address or
because the page was simply removed from the Web.
IEEE.
Institute of Electrical and Electronic Engineers.
IITF.
Information Infrastructure Task Force.
This
organization, established by the Clinton Agency, is comprised of
the Federal agencies specializing in information and
telecommunications technology development and application, with
the goal of outlining and implementing a plan for the National
Information Infrastructure (NII).
Image Processing.
Process of modifying data representing an
image, typically to ameliorate diagnostic interpretation, using
algorithms.
Image Technology.
The component of computer applications that
transform documents, illustrations, photographs, and other images
into data that computers and special-purpose workstations are
capable of storing, distributing, accessing, and processing.
Independent Telephone Company.
A local exchange carrier that
is independent of the Bell system of operating companies (BOCs).
In rural locations, many of the independent telephone companies
are cooperative.
Informatics.
The use of computer science and information
technologies to the management and processing of data,
information and knowledge.
Integrated Circuit.
A solid state microcircuit comprised of
interconnected semiconductor components diffused into a single
instrument.
Interface.
The connection between two devices; applies to both
hardware and software.
Internet.
The most formidable global network of business and
personal computers connected through regular and high-speed
telephone lines. It needs specific types of software to access
it, such as a Web browser. It links computers and computer
networks from colleges and universities, government agencies,
institutions, and commercial organizations worldwide.
Internet Protocol.
Based on the Web site's technical address,
this is another way for accessing Web sites. The formal for this
protocol is a four-part number, such as 207.87.223.39.
ISDN.
Integrated Services Digital Network.
A completely
digital telephone system that is slowly enjoying more popularity
throughout the United States which permits the integrated
transmission of voice, video, and data to users at a higher speed
than would be possible over typical telephone lines. It also
provides connections to a universal network. It currently
requires special installation and equipment.
ISO.
International Organization for Standardization.
Comprised
of national bodies elected to set standards, this non-treaty
organization is involved in illustrating norms for all
communications fields except electrotechnical.
ISO/OSI.
International Organization for Standardization/Open
Systems Interconnections.
The typical reference archetype for
local area network (LAN) architecture. The model is made up of
several hierarchical levels (physical, data link, network,
transport, session, presentation, and application) that address
LAN design, from the specification of the physical transmission
medium to the abilities of user interaction with LAN
services.
IT.
Information Technology.
Using a variety of techniques, it
refers to the storage, manipulation, and communication of
information in audio, data, and video formats.
ITU.
International Telecommunications Union.
This union,
governed by a treaty and comprised of government
telecommunications agencies, is responsible for setting standards
for radio, telegraph, telephone, and television.
ITU-T.
International Telecommunications Union Consultative
Committee for Telecommunications.
Formerly the Consultative
Committee on International Telephone and Telegraph (CCITT). An
international agency responsible for developing standards for
telecommunications, including FAX and video coder-decoder
devices.
IXC.
Interexchange Carrier.
Also referred to a long-distance
carrier, a telephone company that carries long-distance
calls.
Java, Javascript.
Two independent, but related programming
languages that are largely Web-based. They permit augmented
functionality of and enhancements to a Web site. If one's browser
is unable to use these languages, the enhancements or features
found in the Web site will usually not be displayed. Netscape and
Microsoft support both types of languages.
JCAHO.
Joint Commission on Accreditation of Healthcare
Organizations.
JPEG.
Joint Photographic Experts Group.
An algorithm and
standard for compressing digital photographic images. Related to
GIF.
Kb.
Kilobyte.
A measure of computer storage and memory
capacity. Equivalent to 1,024 bytes; often applied to 1,000 bytes
as well.
Kbps.
Kilobits per second.
A measure of bandwidth and rate of
data flow in digital transmission. One Kbps is 1,024 kilobits per
second.
LAN.
Local Area Network.
A network of computers, generally
small in number, whose reach is limited, typically within a
building or campus, linked to allow access and sharing of data
and computer resources by users. Differentiated from MAN and WAN
by the size of the area, LAN is the smallest.
LATA.
Local Access Transport Area.
The local telephone
districts that were created by the divesture of the Regional Bell
Operating Companies (RBOCs) formerly associated with
AT&T.
LDC.
Long Distance Carrier.
Also referred to as Interexchange
Carrier (IEC).
Leased Lines.
A line rented from a telephone company by a
customer so that s/he may have exclusive rights to it. May also
be called a dedicated line.
LEC.
Local Exchange Carrier.
A telephone company that carries
local calls.
Lossless.
A format of data compression, typically of an order
of less than 2:1, in which none of the original data information
is lost when the image is reproduced.
Lossy.
A process of data compression at a relatively high
ratio, which leads to some permanent loss of information upon
reconstruction.
LSTAT.
Luminance Life Support for Trauma and Transport.
The
amount of light an object gives off. Perceived luminance is
denoted as brightness. Although the terms brightness and
luminance are sometimes used interchangeably they are not
equivalent.
Mailing List.
Conducted exclusively through e-mail this is a
discussion group open to the public. Once a user subscribes to a
mailing list, all messages s/he sends to the list and copied and
sent to all other members of the mailing list. A popular method
of engaging in on-line topic-specific discussions. Mailing Lists
are sometimes referred to as "listservs" or majordomos:" named
after the types of software used to maintain them.
MAN.
Metropolitan Area Network.
A network of computers whose
reach extends to a metropolitan area. MANs may be used to link
telemedicine applications at a data rate similar to DS1. In some
cases, MANs may be used by cable companies to offer links to
off-network services such as the internet, airline reservation
systems, and commercial information services, in addition to data
exchange abilities. Compared to LAN and WAN, MAN is in between
the two.
MATMO.
Medical Advanced Technology Management Office.
Developed and implemented by the Department of Defense, this
imaging system combines PACS and teleradiology networks.
Mb.
Megabyte.
A measure of computer storage and memory
capacity. One Mb is equivalent to 1.024 million bytes, 1,024
thousand bytes, or 1.024 kbs. However, this term is also applied
to the more rounded term of 1 million bytes.
Mbps.
Megabits per second.
A measure of bandwidth and rate of
data flow in digital transmission. One Mbps is equivalent to one
million bits per second.
MCU.
Multipoint Control Unit.
Offered by switched network
providers, this centrally located service allows three or more
user to be connected, allowing audio and video
teleconferencing.
MEDIX.
Medical Data Interchange Standard.
Established by the
IEEE, this data communication protocol is utilized at the
applications level.
Medical Informatics.
A system comprised of computer science,
information science, and health sciences created to assist in the
management and processing of data to support the execution of
health care.
Message Switching.
A message either in image or text form that
is separated into multiple parts that are then transmitted
independently to the receiver where they are put back together to
form the message.
Mhz.
Megahertz.
A measure of bandwidth and rate of information
flow for analog transmission. One Mhz equals 10 to the sixth
power cycles per second.
Microwave Link.
A system of communication using high frequency
radio signals, exceeding 800 megahertz, for audio, video, and
data transmission. These links require line of sight connection
between transmission antennas.
Mirror.
A Web site identical to another Web site at a
different physical location. This process is typically used to
expedite access because the original site resides on another
continent. For example, a Web site may be set up in America
duplicating an already existing Web site in Europe so that
Americans can quickly access the site.
Modem.
Modulator/De-modulator.
A device that translates
digital signals to pulse tone (analog) signals to enable
transmission over telephone lines and reconverts them to digital
form at the point of reception, thus permitting a computer to
communicate with another computer over a regular telephone line.
These devices are usually identified by the speed (in bits per
second or bps) of communication they permit. The higher the bps,
the faster the modem.
Moderated.
Used to refer to either mailing lists or
newsgroups, a moderated forum is one in which every message sent
to the forum is first analyzed by an individual called the
"moderator." If the message is germane to the forum's topic, and
is appropriate, it will be approved and published on that forum.
If it is not acceptable, the message is returned to the author.
Distinguished from open and closed.
Monochrome Monitor.
Also known as a gray-scale monitor. A
visual display on a computer that presents images as various
shades of gray, ranging from black to white.
MPEG.
Motion Picture Experts Group.
A standard for compressing
digital video images.
Multimedia.
A term which broadly applies to the transmission
and manipulation of any form of information, including words,
pictures, videos, music, numbers, or handwriting. This
information is regarded as simply digital bits-zeroes and ones-as
it is to a digital telecommunications link that carries
information in bit form. The substantial increase in computing
power permits integrated patient records with audio and video
clips.
Multiplexer.
By combining and interweaving low-capacity
channels in discrete time or frequency slices, this equipment
allows transmission of multiple lines of audio, video or data
information in one high-capacity communications channel.
Narrowband.
A telecommunications medium that uses low
frequency signals, not exceeding 1.544 Mbps.
NCHSR.
National Center for Health Services Research.
Former
name of the Agency for Health Care Policy and Research
(AHCPR).
NEMA.
National Electrical Manufacturers Association.
NetPhone.
Commonly referred to as the "Internet telephone."
Refers to the equipment used to permit two users to talk to one
another using the Internet as the connection.
Netiquette.
Rules of etiquette for online interactions.
Network.
A set of nodes, points or locations which are
connected via data, voice, and video communications for the
purpose of exchanging information.
Network.
Interconnected telecommunications equipment used for
data and information exchange. Consists of different types, LAN,
MAN, and, WAN being examples.
Newsgroups.
Sometimes referred to collectively as "Usenet."
Discussion groups open to the public where users can read the
information posted and add new messages, or articles. Uses a
hierarchical topic structure to make it easy for the user to find
the information. Messages posted to newsgroups are sent to every
computer connected to the Internet, where it is stored for a few
days to give interested users the chance to read it. Individual
users have the option whether they would like to subscribe to
newsgroups. Currently, over 18,000 newsgroups exist and are
available for subscription, although most users only subscribe
to, read, and respond to a few of them.
Newsgroup Reader.
The software used to access, read, and post
to newsgroups.
NHSC.
National Health Service Corps program.
NII.
National Information Infrastructure.
A United States
government policy developed by the Clinton Administration that
involves the synthesis of hardware, software, and skills that
will make it easy and affordable to connect people with each
other, with computers and with a wide variety of services and
information resources.
NIMH.
National Institute of Mental Health
NLM.
National Library of Medicine.
Node.
A branching or exchange point for networks.
NTIA.
National Telecommunications and Information
Administration.
The federal agency in the Department of Commerce
responsible for the National Information Infrastructure
initiative.
NTSC.
National Television System Committee.
An independent
panel that is involved in setting the standards for broadcast
television in the United States. The standard for the NTSC is
sometimes considered a "composite video," because all video
information is combined into one analog signal.
OCR.
Optical Character Recognition.
Automatic scanning the
translation of printed characters to computer-based text.
Open.
Refers to a type of mailing list. Signifies a system
which permits anyone to post a message to it, independent of
their member status. Different than closed or moderated.
Operating System.
The underlying system software which enables
a computer to operate. Common operating systems include DOS,
Windows, and Macintosh System 7x.
Operator.
A character used to limit or broaden a search.
Operators such as and, or, and not are referred to as a "Boolean
operator."
Optical Disk.
A computer storage disk used solely for large
quantities (Gbs) of data.
OSI.
Open Systems Interconnect.
The standard reference model
for local area network (LAN) systems.
OTA.
Office of Technology Assessment.
Agency established by
the United States congress, it was terminated in 1996.
Packet.
A basic message unit for communications in networks. A
short block of data comprised of data, call control signals and
error control information and containing information on its
source, content and destination that is transferred in a packet
switched network.
Packet Network.
A network that gives out data bits in
packets.
Packet Switching Network.
May also be known as the Packet
Switched Network (PSN). This term refers to the transmission of
digital information using addressed packets that are transmitted
along various routes in a network. This system is more efficient
than modem transmission where the channel is occupied throughout
the transmission, because the occupation in the channel is
limited to packet transmission.
Packet Switching.
The procedure of transmitting digital
information via an addressed packets so that a channel is
occupied only during the transmission of the packet.
PACS.
Picture Archiving and Communications System.
A system
capable of acquiring, transmitting, storing, retrieving, and
displaying digital images and relevant patient data from various
imaging sources and communicates the information over a
network.
PBX.
Private Branch Exchange.
A computerized private telephone
switchboard with an extended scope of data and voice services.
This exchange generally serves one organization and is connected
to the public telephone network.
PCM.
Pulse Code Modulation.
A process of encoding audio
signals.
PDF.
Portable Document Format.
Permits the user to read a
document and print it out using Adobe's Acrobat reader, a free
piece of software. PDF files may only be read or printed using
this software.
Peripheral.
Any device that is attached to a computer
externally. Scanners, mouse pointers, printers, keyboards, and
monitors are all examples of this.
PET.
Position Emission Tomography.
Phosphor.
The coating on the inside of a cathode ray tube
(CRT) or monitor that produces light when hit by an electron
beam.
Pixel.
Stands for picture element. This is the smallest piece
of information that a CRT is able to display, and is symbolized
by a numerical code in the computer. Pixels appear on the monitor
as dots of a specific color or intensity. There are many, many
pixels in a single image.
Post.
The process of adding a new message or article to a
newsgroup, conference, or mailing list discussion area
online.
POTS.
Plain Old Telephone Service.
PPO.
Preferred Provider Organizations.
PPP.
Point to Point Protocol.
A type of computer protocol used
by modems for online communication.
PPRC.
Physician Payment Review Commission.
Protocol.
A system of guidelines and procedures, applying to
both hardware and software, that oversees communications between
two computer devices. They are primarily concerned with three
aspects of the communication process: how data are symbolized and
coded, how data are transmitted, and, in file transfer protocol,
how errors and failures are recognized and corrected.
PSTN.
Public Switched Telephone Network.
The public telephone
network.
RAM.
Random Access Memory.
The temporary memory area on a
computer that permits the user to run software, process images,
and store information. The amount of RAM needed varies according
to the application. Increasing the amount of RAM in a computer
can improve computer performance. Information stored in the RAM
is lost when the power is shut off.
RANs.
Rural Area Networks Shared-usage networks.
Designed to
include a wide scope of users in rural communities, such as
educational, health, and business entities.
RBOC.
Regional Bell Operating Company.
Refers to one of seven
regional companies formed by the AT & T divestiture.
Real Time.
The capture, processing, and presentation of data,
audio, and/or video signals at the time the data is originated on
one end and received at the other end. When signals are received
at rates of 30 frames per second, real time is achieved.
Repeater.
A bi-directional instrument used to amplify or
regenerate signals.
Resolution.
Refers to the ability of a device to distinguish
between various factors. For example, spatial resolution is the
ability to distinguish between adjacent structures. Contrast
resolution is the ability to discriminate between shades of
gray.
RIS.
Radiology Information System.
A synthesized system for
the electronic processing, storage and transmission of
radiographic images. RIS allows the remote interpretation of
radiographic image-teleradiology-and may be connected to Hospital
Information Systems (HIS) and Laboratory Information Systems
(LIS).
RMDS.
Navy Remote Medical Diagnosis System.
ROC.
Receiver Operating Characteristic.
A procedure involving
statistics used to analyze the ability of a diagnostic tool to
determine whether an individual is healthy or diseased. ROC
serves are most often used in observer performance evaluations of
the feasibility and performance of diagnostic imaging
systems.
ROM.
Read Only Memory.
The permanent memory capacity for a
computer. programs and information stored in ROM are not lost
when power is extinguished.
Routing.
The assignment of a path of communication.
RTF.
Rich Text Format.
A series of word processing directions
that are able to be read by the majority of word processing
programs in order to retain the formatting rules of the
document.
SAF.
Store and Forward.
A telemedicine interaction type that
creates a multimedia electronic medical record. Data and images
are captured and stored for later transmission, consultation or
downloading. These static images or audio-video clips may be
transmitted to a remote data storage device, from which they may
be retrieved by a medical practitioner for review and
consultation at any time, obviating the necessity of simultaneous
availability of the consulting parties and reducing transmission
costs due to low bandwidth requirements.
Satellite.
An electronic retransmission instrument serving as
a repeater, which is a bi-directional device used to amplify or
regenerate signals, placed in orbit around the earth in
geostationary orbit for the purpose of receiving and
retransmitting electromagnetic signals. It typically receives
signals from a single source and retransmits them over a wide
geographic area, known as the satellite's "footprint."
Satellite Connections.
A system of communications that uses
radio signals sent to and from a satellite orbiting the Earth.
The benefits of this mode of communication are that it allows
connection between points at a great distance from each other on
the Earth's surface, between which direct transmission is
difficult, as well as to remote areas that lack cables for
telephone lines.
SCSI.
Small Computer Systems Interface.
An interface system of
rules and procedures used to connect peripherals such as disk
drives, scanners, and tape back-up units, to computers. SCSI is
also referred to as "scuzzy."
SDM.
Shared Decision Making.
A style of decision-making in
health care where the patient is able to take a more active role
in decision making, especially by offering them increased control
over the choice of treatment, and, as a result, giving them a
greater sense of responsibility for their care and health. Also
called SDP, or Shared Decision Programs.
Search Engine.
A Web site that indexes an online resource and
makes that index available to other users for searching. This
term is typically applied to a site that has indexed Web
documents, but search engines also index mailing lists and other
online resources. An "internal" search engine index only includes
the documents of that particular Web site, which permits the user
to find information on that site more easily and quickly.
Server.
A computer designated to providing specific services
to other computers. For example, print servers only accept,
store, and print out documents sent to them by other computers,
and nothing else. Web servers permit users from around the world
to access the Web sites and documents stored on them.
Shareware.
Computer software that the author gives license to
the user to "try before you buy." Users are encourages to try the
software, copy it and distribute it to other users. If the user
continues to use the software after the initial sampling, a
voluntary payment of a specific sum of money is required. Failure
to pay the requested fee is a legal violation of the author's
copyright.
Site.
An area or location online, typically on the Web, where
an organization, individual or business stores its
information.
SLIP.
Serial Line Internet Protocol.
A kind of computer
protocol used by modems for online communication.
Slow-scan.
The speed of still video image transmission, which
is typically over narrow communications channels such as standard
telephone lines.
Slow-scan Video.
The device that transmits and receives still
video images over a narrow communications channel, such as a
standard telephone line.
SONET.
Synchronous Optical Networks.
A broadband, wide area
communications service capable of transmitting extremely high
capacity data, such as interactive video, at very high speeds
ranging from 150 Mbps to 10 Gbps. SONET services are convenient
for real-time digital telemedicine applications.
Spam.
Messages which are topic irrelevant usually taking the
form of advertisements and are sent to wide variety of discussion
forums (mailing lists or newsgroups), or e-mail addresses online.
This practice, known as "spamming" is discouraged in the online
world.
Spatial Resolution.
Characteristic of being able to
distinguish two equal sized adjacent objects in the same place.
Represents the number of pixels in a specified area of a
matrix.
SPECT.
Single-photon emission computed tomography.
SS7.
Signaling System 7.
A recent development in control
systems for the public telephone network enabling faster
processing and more efficient telephone service, plus making more
services available to consumers.
Standards.
Agreements on how to implement technologies.
Structured Data Entry.
A method of data collection that
constrains the content and format of clinical descriptions for
the purpose of ensuring consistent, unambiguous, interchangeable
messages.
Switch.
A mechanical or solid state device that opens or
closes circuits, varies operating parameters, or chooses paths or
circuits on a space or time division basis.
Switched Line.
Communication link for which the physical path,
established through dialing, may change with each use.
Switched Network.
A system of telecommunications where each
user has a separate address and any two points can be linked
directly, using any combination of available routes in the
network.
Switched Service.
A telecommunications service, often based on
telephone technology, that switches circuits to connect multiple
points.
Synchronous Transmission.
The method by which bits are
transmitted at a fixed rate with the transmitter and receiver
synchronized, extinguishing the need for start/stop elements,
with the result of providing increased efficiency.
T1.
A type of telephone line service offering high-speed data
or voice access, with a transmission rate of 1.544 Mbps. It is
also known as D1.
T3.
A digital transmission system for high volume voice, data,
or compressed video traffic, with a transmission rate of 44.736
Mbps. It is also known as D3.
T-carrier.
A series of transmission systems using pulse code
modulation technology at different channel capacities and bit
rates to transmit digital information over telephone lines or
other transmission medium.
Tariffs.
Price guidelines for communication facilities,
governed by federal or local governments, intended to permit
telephone companies (LATA, see local access transport area) a
fair rate of return on their capital investments.
Tb.
Terabyte.
A measure of computer memory and the quantity of
storage capacity available on a computer. One Tb is equivalent to
one trillion bytes, or ten to the twelfth power bytes. See also
gigabyte, kilobyte, and megabyte.
Tbps.
Terabits per second.
A measure of bandwidth and rate of
information flow in digital transmission. One Tbps is equivalent
to one trillion bits per second.
TCP/IP.
Transmission Control Protocol/Internet Protocol.
The
underlying communications rules and procedures that allow
computers to interact with each other on the Internet.
TDM.
Time Division Multiplexing.
Transmission of more than one
lines of information in one high-capacity communications channel
using time as the means to separate channels.
Telecommunications.
The use of wire, radio, visual, or other
electromagnetic channels to transmit or receive signals for
voice, data , and video communications.
Teleconferencing.
Interactive electronic communication between
multiple users at two or more sites which facilitates voice,
video, and/or data transmission systems: audio, audiographics,
computer and video systems.
Teleconsultation.
The physical separation between multiple
providers during a consultation.
Telediagnosis.
The detection of a disease as a result of
evaluating data transmitted to a receiving station from
instruments monitoring a remote patient.
Telehealth.
The use of electronic communications networks for
the transmission of information and data focused on health
promotion, disease prevention, diagnosis, consultation,
education, and/or therapy, and the public's overall health
including patient/community education and information,
population-based data collection and management, and linkages for
health care resources and referrals. Although telehealth is
sometimes considered broader in scope than telemedicine, there is
no clear-cut distinction between the two.
Telematics.
The use of information processing based on a
computer in telecommunications, and the use of telecommunications
to permit computers to transfer programs and data to one
another.
Telemedicine.
The use of audio, video, and other
telecommunications and electronic information processing
technologies for the transmission of information and data
relevant to the diagnosis and treatment of medical conditions, or
to provide health services or aid health care personnel at
distant sites.
Telementoring.
The use of audio, video, and other
telecommunications and electronic information processing
technologies to provide individual guidance or direction. An
example of this help may involve a consultant aiding a distant
clinician in a new medical procedure.
Telemetry.
The science and technology of automatic measurement
and transmission of data via wires, radios, or another medium
from stations based in remote locations to receiving stations for
recording and analysis.
Telemonitoring.
The process of using audio, video, and other
telecommunications and electronic information processing
technologies to monitor the health status of a patience from a
distance.
Telepresence.
The method of using robotic and other
instruments that permit a clinician to perform a procedure at a
remote location by manipulating devices and receiving feedback or
sensory information that contributes to a sense of being present
at the remote site and allows a satisfactory degree of technical
achievement. For example, this term could be applied to a surgeon
using lasers or dental handpieces and receiving pressure similar
to that created by touching a patient so that it seems as though
s/he is actually present, permitting a satisfactory degree of
dexterity.
Teletext.
A broadcasting service utilizing several otherwise
unused scanning lines (vertical blanking intervals) between
frames of TV pictures to send data from a central database to
receiving television sets.
Telnet.
An application program that permits users to logon to
any computer on the Internet for interaction with other users.
For example, a telnet program may be used to peruse library
holdings and receive results.
Terrestrial Carrier.
A telecommunication transmission system
using land-based facilities such as microwave towers, telephone
lines, coaxial cable, or fiber optic cable as differentiated from
satellite transmission.
Thread.
Messages on an individual topic that appear in the
order they were sent in an online discussion forum, such as on a
newsgroup. This system makes reading of a particular subject
easier, because all of the relevant messages are grouped
together.
Throughput.
The amount of data that is actually transmitted
over a network in a given period of time, expressed in bits per
second. Throughput rates are related to baud rates, but are
generally little lower due to imperfect transmission conditions.
Usually, higher baud rates will permit higher throughput.
Tie Line.
A telephone circuit leased or dedicated to an
individual which is provided by common carriers that connect two
points together without using the switched telephone network.
Translator.
A broadband network operation. A translator is an
instrument, located in a central retransmission facility to
filter incoming microwave signals and retransmit them in a higher
frequency band.
Transmission Speed.
The speed at which information passes over
a communications channel; generally given in either bits per
second (bps) or baud.
Transponder.
A microwave receiver and transmitter in a
satellite that receives signals being transmitted from Earth,
amplifies them, and sends them back down to Earth for reception
purposes.
Trunk.
A large capacity, long-distance channel that common
carriers use to transfer information between its customers.
Turn-key System.
A system of telecommunications in which all
of the installation services and components needed for
operational teleconferencing have been provided by a single
vendor or contractor.
Twisted Pair.
The most common type of medium in PSTN's (public
switched telephone network) local loops, insulated copper wires
are wrapped around each other to void the effects of electrical
noise. It can transmit voice, data, and low-grade video.
UHF.
Ultrahigh Frequency.
A radio frequency in the second
highest range of the radio spectrum, from 300 to 3,000 MHz.
Uplink.
The link, or path, from a transmitting earth station
to the satellite. The term is typically referring to a
transmitting earth station.
Upload.
Transferring files or software from one computer to
another.
URL.
Uniform Resource Locator.
The standard form for an
address on the Internet. For example, http://www.vase.org/
indicates a Hypertext Transport Protocol (http) address on the
World Wide Web (www) with location "vase" and the type of owner
(org). Other valid guidelines may include ftp and gopher. Unlike
most e-mail addresses, URLs are always case sensitive, that is,
whether a character is upper or lower case does make a
difference.
User Interface.
The graphic and design components of a Web
page that directs users on how to access the information
contained in that Web site.
V.32 bis.
International standard for data communications using
a modem at speeds of up to 14,400 bits per second.
V.34 bis.
International standard for data communications using
a modem at speeds of up to 28,800 bits per second. When
purchasing a modem, the user should look for this feature.
Validity.
The extent to which a situation observed reflects
the actual situation.
VFC.
V-Fast Class.
Introduced prior to the V34, this
proprietary modem modulation used for 28.8 Kbps connections, is
no longer a supported standard.
VGA.
Videographics Array.
A measure of image size,
representing the capacity to display 640 X 480 lines, such as on
viewing monitors for personal computers.
VHF.
Very High Frequency.
A radio frequency in the very high
range of the radio spectrum, from 30 to 300 MHz.
Videoconferencing.
Actual-time, generally two way transmission
of digitized video images between multiple locations; uses
telecommunications to bring people at physically remote locations
together for meetings. Each individual location in a
videoconferencing system requires a room equipped to send and
receive video.
Video Frame Grabber.
An instrument that changes an analog
video signal into a set of digital values.
Virtual Circuit.
Packet switched network facilities that
appear to be an actual end-to-end circuit.
Virtual Reality.
A computer-based technology for simulating
visual, auditory, and other sensory aspects of complex
environments to create an illusion of being a three-dimensional
world. That world is designed by the computer, and viewed through
a special headset that responds to your head movements while a
glove responds to your hand movements. For example, while in a
virtual room you may move your hand up in order to fly or tap to
change the color of a wall.
Voice Grade Channel.
A telephone circuit of adequate bandwidth
to carry signals in the voice frequency range of 300 to 3400
Hertz. This is the bandwidth of a POTS line.
Voice Recognition.
The ability of a computer to interpret
auditory information in the form of spoken words.
Voice Switching.
An electronic method for opening and closing
a circuit, such as changing form one microphone to another
microphone or from one video camera to another video camera,
responding to the presence or absence of sound.
Voxel.
Volume Element.
A voxel is like a pixel in a
three-dimensional version and is generated by computer-based
imaging systems, such as CT or MRI.
VRAM.
Video Random Access Memory.
VTC.
Video Teleconferencing.
WAN.
Wide Area Network.
Data communication networks that links
together distant networks and their computers to provide
long-haul connectivity between separate networks located in
different geographic areas.
Wildcard.
Typically represented by an asterisk (*), a wildcard
symbol permits the user to conduct an open-ended search. It may
be used to ensure a search turns up all forms or derivatives of a
word. For example, chil* will turn up both child and
children.
WATS.
Wide Area Telephone Service.
A telephone service with a
flat rate for measured bulk-rate, long distance services given on
an incoming or outgoing basis. WATS allows a consumer, by use of
an access line, to make telephone calls to any telephone number
that is able to be dialed in a specific zone for a flat or bulk
monthly rate using an 800 number.
Window Width.
The range of the gray scale of the image seen on
a screen. The middle value is the "window level."
Workstation.
A grouping of computer hardware and software
(e.g. monitor, keyboard, hard drive) functioning for individual
uses such as word, information, and image processing.
WRAIR.
Walter Reed Army Institute for Research
WWW.
World Wide Web.
Also known as "the Web." An Internet
information resource for international hypertext linking which
offers graphics, sound, text, and in some cases video clips
giving information. This is the newest (1993) and fastest growing
aspect of the Internet because of its ability to offer more than
just plain text online.
Zip.
An extension for a file name indicating the file is
indexed and compressed using Phil Katz's PKZIP compression
utilities. A program, called "pkunzip.exe" is needed to
decompress and extract the programs within this file.
