Telemedicine, Telehealth, and the Consumer

Telemedicine and Telehealth Glossary

1. ADSL.
   Asymmetrical Digital Subscriber Line. Refers to a pair of modems connected by a copper line that yields asymmetrical transmission of data.
2. Amplifier.
   Electronic devices that strengthen a signal as it passes along a communications channel.
3. 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.
4. ANSI.
   American National Standards Institute.
5. Architecture.
   The selection, design, and interconnection of the hardware of a computer system.
6. 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.
7. ARPANET.
   Advanced Research Projects Agency Network.
8. 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.
9. 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.
10. ATLS.
    Advanced Trauma Life Support. The basic skills for resuscitation employed by emergency care workers.
11. 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.
12. Audio-teleconferencing.
    Two way communications between multiple people at various locations.
13. Authentication.
    A method of verifying the identity of the person sending or receiving information by use of passwords, keys and other automated identifiers.
14. Automated Data Collection.
    The direct transmission of physiological information from monitoring devices to either a bedside display system or a computer-based patient record.
15. B-CDMA
    Broadband Code Division Multiple Access. A form of wireless technology where digital information is sent over communication networks.
16. 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.
17. 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.
18. 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.
19. 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.
20. BOCs.
    Bell Operating Companies. Grouped under the seven Regional BOCs.
21. 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.
22. Brightness.
    The perception of luminance by the human eye. Although many use luminance and brightness interchangeably, they are not exact synonyms.
23. 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.
24. Browser.
    Also known as a Web browser. Any program that permits access and searches on the World Wide Web.
25. 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.
26. Byte.
    A string or cluster of eight bits to represent a character.
27. Cable television (CATV).
    A transmission system that distributes broadcast television signals and other services by means of a coaxial cable.
28. CAD.
    Computer-aided Design.
29. CATV.
    Cable Television. A system of transmission that distributes broadcast television signals and other various services via a coaxial cable.
30. 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.
31. 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.
32. 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.
33. CDC.
    Center for Disease Control.
34. 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).
35. CEN.
    European Technical Committee for Normalization. An international agency responsible for setting standards in health care informatics.
36. Channel.
    A radio frequency assignment designed depending on the frequency band being used and the geographic location of the sending/receiving sites.
37. 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.
38. 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.
39. 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.
40. 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'.
41. CME.
    Continuing Medical Education.
42. CMHCs.
    Community Mental Health Centers.
43. 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.
44. 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.
45. 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.
46. 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.
47. 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.
48. Communication Multiplexer.
    An instrument that permits data from multiple, lower speed communication lines to share a single higher speed communication path.
49. 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.
50. 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.
51. 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.
52. 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.
53. Computer-based Patient Record (CPR).
    A compilation in electronic form of individual patient information that resides in a system designed to provide access to complete and accurate patient data, alerts, reminders, clinical decision support systems, links to medical knowledge, and other aids.
54. Computer Conferencing.
    Communications within groups through computers, or the use of shared computer files, remote terminal equipment, and telecommunications channels for two-way communication.
55. 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.
56. Connectivity.
    The ability to send and receive information between two locations, devices, or business services.
57. 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.
58. CPRI.
    Computer-based Patient Record Institute, Inc. An independent institute that develops and recommends standards for computerized patients records.
59. CPU.
    Central Processing Unit. The device in a computer that executes directions in software programs and performs calculations and other operations.
60. CRT.
    Cathode Ray Tube. The monitor or other means of displaying data in a computer system.
61. Crawlers.
    The software used to index the World Wide Web. Also referred to as 'robots' and 'spiders.'
62. 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.
63. Data Repository.
    The element of an information system that accepts, files, and stores data from various sources.
64. 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.
65. 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.
66. 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).
67. 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.
68. 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.
69. 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.
70. 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.
71. 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.
72. 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.
73. 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.
74. Direct Broadcast Satellite (DBS).
    A satellite designed with sufficient power so that inexpensive earth stations, or downlinks, can be used for direct residential reception.
75. 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.
76. Direct Digital Imaging.
    Involves the capture of digital images so that they can be electronically transmitted.
77. Dish.
    An antenna shaped like a parabola that is the essential component of a satellite earth station, or downlink.
78. 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.
79. Downlink.
    The path from a satellite to the Earth stations that receive its signals.
80. Download.
    The process of transferring files or software from another computer to your computer.
81. 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).
82. 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.
83. Duplex.
    A transmission system permitting data to be transmitted in both directions simultaneously.
84. Dynamic Range.
    The characteristic of a communications or imaging system to reproduce or transmit various brightness levels.
85. Earth Station.
    The ground equipment essential for receiving and/or transmitting satellite telecommunications signals.
86. 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.
87. 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.
88. 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.
89. Ethernet.
    A communications protocol that utilizes various types of cable at a rate of 10 Mbps.
90. 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.
91. FAQ.
    Frequently Asked Questions. A file developed for many public discussion groups that consist of popular questions and their answers.
92. Fax.
    Facsimile. A device which enables a user to electronically transmit and reproduces documents over telephone lines.
93. FDDI.
    Fiber Distributed Data Interface. A high-speed fiber optic network containing a state-of-the art bandwidth.
94. 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.
95. 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.
96. Film Digitizer.
    An instrument that permits scanning of existing static images so that the images may be stored, manipulated, or transmitted in digital form.
97. Filmless Radiology.
    Use of devices that replace film by acquiring digital images and related patient information and transmit, store, retrieve, and display them electronically.
98. Firewall.
    Computer hardware and software designed to prevent unauthorized communications between an institution's computer network and external networks.
99. 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.
100. Footprint.
     The geographic range on the earth beneath a satellite that is in the scope to receive that satellites information.
101. 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.
102. 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.
103. 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.
104. Frequency.
     The rate at which an electromagnetic signal alternates, denoted in Hertz.
105. 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.
106. 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.
107. 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.
108. 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.
109. Gbps.
     Gigabits per second. A measure of bandwidth and rate of data flow in digital transmission.
110. 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.
111. Ghz.
     Gigahertz. One billion cycles per second. It measures analog signal transmission.
112. 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.
113. 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.
114. 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.
115. 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.
116. 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.
117. GUI.
     Graphical User Interface. A method of controlling computers using graphic images or icons, to which the user accesses using a mouse.
118. 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.'
119. Half Duplex.
     A channel of communication which is capable of both transmitting and receiving information, but only in one direction at a time.
120. Hard Drive.
     The storage device within a computer used to save data, files, and programs.
121. 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.
122. Hard Wired.
     Refers to the permanent connection of two devices by a communications link.
123. HCII.
     Health Care Information Infrastructure. A subset of the National Information Infrastructure.
124. HDTV.
     High-definition television. A television system with 1125 lines of horizontal resolution, with the ability of creating high quality video images.
125. Hertz.
     A unit of frequency equivalent to one cycle per second.
126. 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).
127. 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.
128. 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.
129. 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.
130. HMO.
     Health Maintenance Organization.
131. 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.
132. 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.
133. 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 .shtml or .shtm suffix.
134. HTTP.
     Hypertext Transport Protocol. The standard by which the World Wide Web operates.
135. 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.
136. IEEE.
     Institute of Electrical and Electronic Engineers.
137. 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).
138. Image Processing.
     Process of modifying data representing an image, typically to ameliorate diagnostic interpretation, using algorithms.
139. 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.
140. 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.
141. Informatics.
     The use of computer science and information technologies to the management and processing of data, information and knowledge.
142. Integrated Circuit.
     A solid state microcircuit comprised of interconnected semiconductor components diffused into a single instrument.
143. Interface.
     The connection between two devices; applies to both hardware and software.
144. 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.
145. 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.
146. 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.
147. 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.
148. 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.
149. IT.
     Information Technology. Using a variety of techniques, it refers to the storage, manipulation, and communication of information in audio, data, and video formats.
150. 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.
151. 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.
152. IXC.
     Interexchange Carrier. Also referred to a long-distance carrier, a telephone company that carries long-distance calls.
153. 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.
154. JCAHO.
     Joint Commission on Accreditation of Healthcare Organizations.
155. JPEG.
     Joint Photographic Experts Group. An algorithm and standard for compressing digital photographic images. Related to GIF.
156. Kb.
     Kilobyte. A measure of computer storage and memory capacity. Equivalent to 1,024 bytes; often applied to 1,000 bytes as well.
157. Kbps.
     Kilobits per second. A measure of bandwidth and rate of data flow in digital transmission. One Kbps is 1,024 kilobits per second.
158. 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.
159. 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 ATT.
160. LDC.
     Long Distance Carrier. Also referred to as Interexchange Carrier (IEC).
161. 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.
162. LEC.
     Local Exchange Carrier. A telephone company that carries local calls.
163. 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.
164. Lossy.
     A process of data compression at a relatively high ratio, which leads to some permanent loss of information upon reconstruction.
165. 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.
166. 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.
167. 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.
168. MATMO.
     Medical Advanced Technology Management Office. Developed and implemented by the Department of Defense, this imaging system combines PACS and teleradiology networks.
169. 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.
170. 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.
171. 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.
172. MEDIX.
     Medical Data Interchange Standard. Established by the IEEE, this data communication protocol is utilized at the applications level.
173. 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.
174. 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.
175. 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.
176. 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.
177. 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.
178. 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.
179. 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.
180. 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.
181. MPEG.
     Motion Picture Experts Group. A standard for compressing digital video images.
182. 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.
183. 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.
184. Narrowband.
     A telecommunications medium that uses low frequency signals, not exceeding 1.544 Mbps.
185. NCHSR.
     National Center for Health Services Research. Former name of the Agency for Health Care Policy and Research (AHCPR).
186. NEMA.
     National Electrical Manufacturers Association.
187. 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.
188. Netiquette.
     Rules of etiquette for online interactions.
189. Network.
     A set of nodes, points or locations which are connected via data, voice, and video communications for the purpose of exchanging information.
190. Network.
     Interconnected telecommunications equipment used for data and information exchange. Consists of different types, LAN, MAN, and, WAN being examples.
191. 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.
192. Newsgroup Reader.
     The software used to access, read, and post to newsgroups.
193. NHSC.
     National Health Service Corps program.
194. 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.
195. NIMH.
     National Institute of Mental Health.
196. NLM.
     National Library of Medicine.
197. Node.
     A branching or exchange point for networks.
198. NTIA.
     National Telecommunications and Information Administration. The federal agency in the Department of Commerce responsible for the National Information Infrastructure initiative.
199. 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.
200. OCR.
     Optical Character Recognition. Automatic scanning the translation of printed characters to computer-based text.
201. 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.
202. Operating System.
     The underlying system software which enables a computer to operate. Common operating systems include DOS, Windows, and Macintosh System 7x.
203. Operator.
     A character used to limit or broaden a search. Operators such as and, or, and not are referred to as a 'Boolean operator.'
204. Optical Disk.
     A computer storage disk used solely for large quantities (Gbs) of data.
205. OSI.
     Open Systems Interconnect. The standard reference model for local area network (LAN) systems.
206. OTA.
     Office of Technology Assessment. Agency established by the United States congress, it was terminated in 1996.
207. 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.
208. Packet Network.
     A network that gives out data bits in packets.
209. 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.
210. 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.
211. 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.
212. 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.
213. PCM.
     Pulse Code Modulation. A process of encoding audio signals.
214. 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.
215. Peripheral.
     Any device that is attached to a computer externally. Scanners, mouse pointers, printers, keyboards, and monitors are all examples of this.
216. PET.
     Position Emission Tomography.
217. Phosphor.
     The coating on the inside of a cathode ray tube (CRT) or monitor that produces light when hit by an electron beam.
218. 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.
219. Post.
     The process of adding a new message or article to a newsgroup, conference, or mailing list discussion area online.
220. POTS.
     Plain Old Telephone Service.
221. PPO.
     Preferred Provider Organizations.
222. PPP.
     Point to Point Protocol. A type of computer protocol used by modems for online communication.
223. PPRC.
     Physician Payment Review Commission.
224. 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.
225. PSTN.
     Public Switched Telephone Network. The public telephone network.
226. 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.
227. 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.
228. RBOC.
     Regional Bell Operating Company. Refers to one of seven regional companies formed by the AT&T divestiture.
229. 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.
230. Repeater.
     A bi-directional instrument used to amplify or regenerate signals.
231. 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.
232. 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).
233. RMDS.
     Navy Remote Medical Diagnosis System.
234. 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.
235. ROM.
     Read Only Memory. The permanent memory capacity for a computer. Programs and information stored in ROM are not lost when power is extinguished.
236. Routing.
     The assignment of a path of communication.
237. 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.
238. 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.
239. 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.'
240. 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.
241. 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.'
242. 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.
243. 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.
244. 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.
245. 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.
246. Site.
     An area or location online, typically on the Web, where an organization, individual or business stores its information.
247. SLIP.
     Serial Line Internet Protocol. A kind of computer protocol used by modems for online communication.
248. Slow-scan.
     The speed of still video image transmission, which is typically over narrow communications channels such as standard telephone lines.
249. Slow-scan Video.
     The device that transmits and receives still video images over a narrow communications channel, such as a standard telephone line.
250. 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.
251. 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.
252. 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.
253. SPECT.
     Single-photon emission computed tomography.
254. 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.
255. Standards.
     Agreements on how to implement technologies.
256. 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.
257. 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.
258. Switched Line.
     Communication link for which the physical path, established through dialing, may change with each use.
259. 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.
260. Switched Service.
     A telecommunications service, often based on telephone technology, that switches circuits to connect multiple points.
261. 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.
262. 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.
263. 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.
264. 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.
265. 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.
266. 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.
267. 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.
268. TCP/IP.
     Transmission Control Protocol/Internet Protocol. The underlying communications rules and procedures that allow computers to interact with each other on the Internet.
269. 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.
270. Telecommunications.
     The use of wire, radio, visual, or other electromagnetic channels to transmit or receive signals for voice, data , and video communications.
271. 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.
272. Teleconsultation.
     The physical separation between multiple providers during a consultation.
273. Telediagnosis.
     The detection of a disease as a result of evaluating data transmitted to a receiving station from instruments monitoring a remote patient.
274. 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.
275. 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.
276. 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.
277. 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.
278. 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.
279. 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.
280. 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.
281. 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.
282. 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.
283. 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.
284. 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.
285. 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.
286. 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.
287. 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.
288. Transmission Speed.
     The speed at which information passes over a communications channel; generally given in either bits per second (bps) or baud.
289. 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.
290. Trunk.
     A large capacity, long-distance channel that common carriers use to transfer information between its customers.
291. 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.
292. 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.
293. UHF.
     Ultrahigh Frequency. A radio frequency in the second highest range of the radio spectrum, from 300 to 3,000 MHz.
294. Uplink.
     The link, or path, from a transmitting earth station to the satellite. The term is typically referring to a transmitting earth station.
295. Upload.
     Transferring files or software from one computer to another.
296. 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.
297. 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.
298. V.32 bis.
     International standard for data communications using a modem at speeds of up to 14,400 bits per second.
299. 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.
300. Validity.
     The extent to which a situation observed reflects the actual situation.
301. 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.
302. 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.
303. VHF.
     Very High Frequency. A radio frequency in the very high range of the radio spectrum, from 30 to 300 MHz.
304. 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.
305. Video Frame Grabber.
     An instrument that changes an analog video signal into a set of digital values.
306. Virtual Circuit.
     Packet switched network facilities that appear to be an actual end-to-end circuit.
307. 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.
308. 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.
309. Voice Recognition.
     The ability of a computer to interpret auditory information in the form of spoken words.
310. 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.
311. 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.
312. VRAM.
     Video Random Access Memory.
313. VTC.
     Video Teleconferencing.
314. 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.
315. 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.
316. 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.
317. Window Width.
     The range of the gray scale of the image seen on a screen. The middle value is the 'window level.'
318. 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.
319. WRAIR.
     Walter Reed Army Institute for Research.
320. 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.
321. 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.