Fiber Optics Illustrated Dictionary networks (e.g., email) rather than through traditional paper submissions. In order to ensure the security and legality of these documents, which cannot be hand- signed by traditional means, the legal system has had to assess the laws of contracts and evidence and emerging digital certificate formats. While some of these issues were worked out in the late 1990s, and digital certificates have received recognition and en- dorsements from the u.s. government, the adjustment to new technologies is ongoing. XML and Adobe PDF are emerging as two popular formats for filling out and submitting forms and applications. Electronic Filing System EFS. The U.S. Patent and Trademark Office (U.S.P.T.O.) system for submitting patent applications, biosequence listings, and pre- grant publications submissions. This system enables applications to be sent electronically through the In- ternet rather than through mail or courier systems on paper. To facilitate and standardize the process, the U.S.P.T.O. provides XML authoring tools, software, and a digital certificate for secure transmission. See Electronic Form System. Electronic Form System EFS. An XML schema definition that provides an extensible specification for platform-independent electronic forms and surveys that can be transmitted through email or Web middle- ware. Electronic Frontier Foundation EFF. A well- known, influential civil liberties association co- founded in 1990 by Mitch Kapor and John Perry Barlow, which acts as a forum and advocate for so- cial and legal issues related to the information and electronic revolution. See American Civil Liberties Union, Electronic Privacy Information Center. http://www.eff.org/ electronic funds transfer EFT. A system through which fmancial transactions are enacted electroni- cally over a network without the actual exchange of physical currency. Stock transactions have typically been carried out this way, especially in the last de- cade, and the exchange of actual stock certificates is not required. Electronic Industries Alliance EIA. A national trade association representing the U.s. high technology in- dustry. The related Government Electronics and In- formation Technology Association (GEIA) includes companies that manufacture or engage in research, development or systems integration to meet the needs of U.S. government agencies. http://www.eia.org/default.htm Electronic IndustriesFoundationElF. The philan- thropic arm of Electronic Industries Alliance, estab- lished in 1976. Elf addresses social/educational is- sues in the electronics industry. Electronic Information Group EIG. The EIG is as- sociated with the Electronics Industries Alliance. http://www.eia.org/ electronic key exchange The process of exchanging public keys in a public key encryption scheme, so messages can be forwarded to the owner of the pub- lic key and decrypted with a corresponding private key. It is used for authentication of electronic 312 communications. Public keys are sometimes up- loaded to public databases on the Internet. Electronic Key Telephone Service EKTS. An ISDN-l standard for supplementary ISDN services. Key telephone systems enable multiline phone sets commonly used by businesses and institutions to di- rectly select outside lines through the central office rather than through local switching equipment Com- mercial vendors of EKTS phone devices have built many features into these systems, including on-hook dialing, programmable function keys, indicator lamps and LEOs, bridging (similar to a conference call within a telephone number group), and more. Visual indicators typically show the line status electronic leash Any mobile communications unit that ties the user to an employer or other entity to which the user has a responsibility or obligation to respond. It particularly applies to those devices that clip to a belt or pocket. Beepers and pagers are good examples, though short-range radios and cellular phones may be included. Electronic leashes are fre- quently used by professionals who are in the field or on call. Short-range radios are now also being mar- keted to families as child-monitors for family outings at parks or malls. (It's considered bad manners to keep a beeper or pager active while watching a live stage performance. ) electronic lock Any locking mechanism activated through software, image recognitions systems or other sensors. Electronic locks are being incorporated into laptops, mobile phones, and cars to deter unau- thorized use. They are also incorporated into some door entry systems. electronic mail, email The invention of email is at- tributed to Ray Tomlinson ofBBN in the early 1970s. Email is the exchange of correspondence through computer networks. In its broadest sense, it includes text files, sound files, graphics, and data files. The exchange of electronic mail is one of the most heavily used capabilities of the Internet, enabling messages to be sent to almost anyone in the world with an In- ternet connection, often without surcharges (unless messages are unusually large), depending upon the Internet Services Provider (ISP). Most email follows basic standardized formats in or- der to maintain platform independence on distributed networks like the Internet. Email headers contain not only information about the source and destination of the message, but they may include various amounts of information about the path of the message and the affiliations of the sender. The header may also include optional information about the format and display of the subsequent message. On distributed network systems, it is not unusual for multiple emails from one source to one destination to take different routes or to be divided into pieces (packets) and sent through various routes, to be reas- sembled at the destination before being made avail- able to the recipient. · In the mid-1980s, it was not unusual for an email message to take two or three days to travel from Bos- ton to San Francisco, for example. Now it is unusual © 2003 by CRC Press LLC for it to take more than a few seconds. A message posted to a public newsgroup, such as USENET, can be sent from a home or office computer and subse- quently downloaded from a local mail server in 15 or 20 seconds, sometimes even faster if the ISP is in a direct link with the backbone supplying the news- group and the newsgroup is unmoderated and does not hold the messages before posting them. Until the late 1990s, most email was text-based, even though graphical email had been available for many years on specific platforms. With the increase in the use of Web browsers for reading and handling email files, however, senders began to send binary file at- tachments, HTML-format messages, and other graph- ics and sound formats, thus significantly increasing file sizes and transmission times for email. By the late 1990s, the volume of unsolicited [com- mercial] email (colloquially termed spam or UCE) had reached such alarming levels that ISPs were forced to put blocks on email with certain character- istics or from certain sites. A remarkable proportion of messages were being sent from fake senders or even fake domain names. As much as 80% of a person's email may be spam, causing an annoyance and time factor in addition to the raw cost. The cost to the ISPs and their users who pay for disk space or connect time, etc. can be very high and is increasing daily as more people connect to the Internet and the multimedia capabilities of the technologies improve. Thus, there have been frequent calls to legislators to do something to stem the tide. On the one hand, ad- vertisers want the freedom to contact potential cus- tomers; on the other, customers and ISPs rightfully don't want to shoulder the cost ofunsolicited or un- desired communications. See Forum for Responsible and Ethical Email. electronic mail gateway In a network where there are links to other networks that may be using a vari- ety of network mail protocols, a gateway system handles receipt, translation (if necessary), and deliv- ery of the messages to the local system, the external system, or both. Mail filters and distribution agents may be incorporated at the gateway level to selec- tively process and deliver email. See electronic mail, Post Office Protocol. electronic mall An online storefront, usually Web- based, that allows consumers to view, review, or re- quest infonnation about products and services. Al- though Web page layouts differ widely, electronic malls are nevertheless beginning to use some com- mon conventions, such as shopping carts which are lists of products that are selected by pressing buttons on the Web page to queue for the final order entry and payment section. As no consistent electronic commerce money transfer schemes have emerged as yet, most of the electronic malls that are successfully getting orders are using credit card ordering. Electronic MarketA model for cross-border, remote electronic commerce in a broader context as defined by initial e-commerce studies of APEC and TELESA. The Electronic Market is a set of rules for interna- tional interconnection of electronic commerce test-beds intended to verify the effectiveness of the concept and its implementation. See Integrated Next Generation Electronic Commerce Environment Project. Electronic Media Forum EMF. Ajoint experimen- tal project of the American Federation of Musicians, the International Conference of Symphony and Op- era Musicians, and the Symphony, Opera, and Ballet Orchestra Managers' Media Committee. This forum tackles the issues of online performances, copyrights, ~~::Ji~~~?Jree::~~~~~ ~~~:::~~nc:~ rg verging multimedia technologies. http://www.electronicmediaforum.org/ Electronic Messaging Association EMA. An orga- nization established to support the development and use of secure global electronic commerce services, including electronic mail, faxing, paging, and com- puting services. EMA contributes to education, pub- lic policy discussions, and connectivity and interoper- ability issues. http://www.ema.org/ J Electronic Payments Forum EPF. An alliance of commercial, nonprofit, academic, government, and standards bodies, committed to furthering the devel- opment and implementation of electronic payment systems to promote global electronic commerce. The EPF is organized under CommerceNet, the Financial Services Technology Consortium (FSTC), and the Cross-Industry Working Team (XIWT) http://www.epf.net/ electronic phone Newer phone technology in which many of the mechanical parts common to traditional phones are replaced with circuit board logic design. This design results in components, such as cellular phones, that are smaller, lighter, and more portable. Electronic Privacy Information Center EPIC. A public interest research center to focus public atten- tion on emerging privacy and civil liberties issues, founded in 1994. EPIC is located in Washington, D.C., and works in association with Privacy Interna- tional in the U.K. EPIC maintains policy archives with information on computer security, encryption, privacy, and freedom of information and speech. It also keeps an archive ofpreviously classified gov- ernment documents obtained under the Freedom of Information Act. It publishes a newsletter on civil lib- erties, tracks legislation, and recommends better texts on privacy and cyber-liberties. See American Civil Liberties Union, Electronic Frontier Foundation, Cyberspace Electronic Security Act of 1999. http://www.epic.org/ electronic receptionistA type of Auto Attendant sys- tem with extra logic and capabilities that allow the personalized notification of messages through a net- work, sometimes even with a graphic animation ofa human receptionist delivering the message. It is likely that electronic receptionist virtual reality scenarios and videoconferencing will create some remarkable systems in the future. See Auto Attendant. Electronic Rights for the21st CenturyActA large U.S. Senate bill (S 854) introduced in April 1999 by Patrick Leahy. It deals with privacy and encryption 313 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary with several areas similar to the Security and Free- dom through Encryption Act. No further action has been taken on this bill. See Security and Freedom through Encryption Act. electronic ringingA digitally encoded sound file that is played instead of the conventional mechanical tele- phone ringer. Since it's digital, it can be made pro- grammable, and thus any sound patch could techni- cally be used as a ringing sound. Just as the error beep on most computer systems can be selected or recorded by the user, electronic ringers will probably be se- lectable in the future. Given the creative bent of many individuals, some likely ringers would include car horns, buzzers, dogs barking, voices saying "You've got a call." Now, if you consider the availability of Caller ill, itwon't be long before someone invents a ringer that not only alerts the person about an incom- ing call but also speaks a message that says, "It's your girlfriend, better answer before she changes her mind!" Phones integrated into personal computers already exist, so it'sjust amatterof time before these are combined with electronic voice mail and custom- ized ringing sounds. electronic serial number ESN. In general, an en- coded identifier for locating or authenticating a de- vice. The degree ofsecurity of these numbers varies widely. In the cellular phone industry, the ESN is a 32-bit code that uniquely identifies a cell phone unit. It is standardized to include aunit number and infor- mation about the manufacturer. Also, there is reserved space for future or specialized use. In some cell phones, the ESN cannot be changed except by those who are handy with electronics and have a custom reprogramming cable and computer connection. When using a cellular phone to make a call, the cell switching center uses the information to check the validity of the caller, and it sometimes checks a da- tabase of cell phones that are reported as stolen. If the number is valid, and there are no problems with the ownership of the unit or the currentness of the ac- count, the call is put through. The ESN is also used as an access code on the Web. Different cell phone manufacturers have various online services, including customer assistance, war- ranty information, etc., which can be accessed by users with legitimate ESN s. Electronic Signatures in Global and National Commerce Act Passed by the U.S. Congress in June 2000 to facilitate global and interstate use and en- forcement of electronic contracts through electronic signatures and records. An important aspect of the Act is related to the receiver's ability to access and deal with electronic documents and the related impact on electronic commerce. Thus, the issue of consent for the receipt of electronic documents, as opposed to traditional paper documents/signatures, on the part of the recipient is being widely discussed. electronic switching system In old phone systems, call connections were established by human opera- tors plugging phone jacks into jack panels. Later, me- chanical switches and electromechanical devices au- tomated the process. Still later, logically programmed 314 solid-state components took over switching functions in conjunction with the telephone switching equip- ment to create electronic switching systems. See Elec- tronic Switching System 1. Electronic Switching System 1, Electronic Switch- ing System lA ESS I/ESS lA. An AT&T computer- controlled electronic telephone crosspoint switching system based upon the IA processor. This is an End Office (Class 5) system that has resulted in a number of additional technologies, including the No. lOA Remote Switching System (RSS). The IAprocessor handles maintenance and administrative tasks asso- ciated with the system switches and provides read- out data for operators and maintenance personnel. It is a digital switch that functions within an analog sys- tem that was first introduced as ESS 1 in the 1960s and ESS lA in the 1970s when end-to-end digital sys- tems were not yet common. It has generally been superseded by newer digital systems (e.g., ESS5). See lA. Electronic Technology Systems ETS. A European global testing and certification body, located near Berlin, Germany. ETS supports a number ofrelated industries, including consumer electronics, telecom- munications, and safety, and provides testing equip- ment for digital mobile markets. electronic yellow pages EYP. An electronic database of business address listings. There are many EYP lookup services on the Web that allow the user to query for a business name or business-related key- word in order to locate a company. The company does not have to be connected to the Web to be listed, as many electronic yellow pages services get their list- ings from local communities or printed directories. See yellow pages, Yellow Pages. electronics The art and science ofinvestigating and harnessing electrons. Some lexicons make adistinc- tion between electron movement through the air or through a vacuum (electronics) as distinct from elec- tron movement through a wire or other similar con- ductor (electricity). While this distinction may be important in a theoretical sense, for the purpose of this general purpose telecommunications dictionary, the broadest sense of the term electronics has been used. The harnessing ofelectrons is fundamental to telecommunications technology. The term came into general use in the 1940s. See magnet, vacuum tube. Electronics Technicians Association, International ETA. A not-for-profit international organization es- tablished in 1978 to support and promote the elec- tronics service industry through education and certi- fication programs. Headquarters are in Indiana. Some programs require that candidates first hold an Asso- ciate Certified Electronics Technician designation, and others do not. Programs include traditional and fiber optics installation certificates. Electronics Telecommunications Research Insti- tute ETRI. A research institute located in Taejon, South Korea, descended from the Korea Institute of Electronics Technology (KIET), established in 1976, and the Korea Telecommunication Research Institute (KTRI), established in 1977. In 1985, KIET and KTRI were merged into ETR! under control of the © 2003 by CRC Press LLC Ministry of Science and Technology; then in 1992, it moved to the control of the Ministry of Science and Technology. In 1995, it was re-established as ajudi- cial foundation through the Electrical Communica- tions Act and three years later was restructured into four technology labs (and later into five labs to posi- tion it as a global leader in core information technolo- gies). ETR! affiliation was moved to the Department of the Prime Minister in 1999. In 2000, the Korean national research institute was made an affiliate ofETRI. ETR! is focused on research in basic and advanced science/engineering and telecommunications tech- nologies, computers, information technology, and semiconductors. Areas ofparticular interest include switching systems, mobile/wireless communications, and semiconductor technology in support of a na- tional telecommunications system. ETR! publishes the quarterly ETRI Journal. In 1994, the U.S. Air Force visited the Institute to learn about the research carried out there and to make initial contacts regarding possible future collabora- tive research programs. http://www.etri.re.kr/ electrophoretic displayA display technology incor- porating positively charged, suspended color particles sandwiched between two outer plates. The suspen- sion medium consists ofa contrasting color so the sus- pended particles are visible or not visible depending on their position within the suspension medium. The particles are moved to the front (visible) or back of the display (not visible) by applying negative and positive voltages through matrix addressing. electroplating The process of using electrode posi- tion to cause a usually metallic substance to adhere strongly to another. Metals are often electroplated to prevent corrosion, to improve conductive properties, or to increase their value (as with gold or silver elec- troplating on jewelry or cutlery). electroscope An instrument for detecting the pres- ence of an electric charge, and whether it is positive or negative. It may also be designed to indicate the intensity of that charge. electrostatic An electrical charge at rest, familiar to many people as static electricity. Static electricity associated with rubbing amber (amber in Greek is elektron) was known to the Greeks by at least 600 BC when Thales recorded that a 'fossilized vegetable rosin' ( amber), when rubbed with silk, acquired the property to attract very light objects to itself. electrostatic charge An electrostatic charge that is stored as in an insulator or capacitor. Subsequent dis- charge must be carefully controlled or prevented in electronic components, as they have the potential to cause harm. See condenser, Leyden jar. electrostatic deflection The process of controlling the path of an electron beam by passing it between charged plates. This system is widely used in cath- ode-ray tubes (CRTs). See cathode-ray tube. electrostatic focusing The process of using an elec- trical field to focus an electron beam. electrostatic plate A type of printing plate incorpo- rated into high speed laser printing processes that uses various metals, chemicals and photoconductors to create and transfer an image. electrostatic printing A printing process in which the imaging is primarily done with electrical rather than chemical means; it is a dry replication process very common in photocopiers and laser printers. Typically, laser beams trace an electrostatic pattern that attracts very fine particles of powder, usually toner, that are subsequently fused onto the printing medium with heat. electrostatic voltmeter A voltage-driven voltage measuring instrument that requires almost no power for its operation. The electrostatic voltmeter functions by using the attracting and repelling properties of magnetic bodies. It can be used on both alternating current (AC) and direct current (DC). Elektro See Geostationary Operational Meteorologi- cal Satellite. ELIU electrical line interface unit. Land Mass-Distributed Orbits The Ellipso project employs some unusual orbits, differentfrom the commongeostationary or regularly elliptic orbits used by other satellite service provid- ers. Ellipso A commercial satellite communications sys- tem based on groupings of low Earth orbit (LEO) bent pipe transponders, operating in a unique elliptical obit through CDMA technology. The Ellipso orbits are adapted to the distribution of land masses and populations on the Earth. Two complementary and coordinated constellations of sat- ellites comprise the Ellipso constellation. The Ellipso- Borealis Subconstellation covers northern latitudes through 10 satellites in elliptical orbits in two planes with apogees of7846 kilometers operating in a three- hour orbital period. The Ellipso-Concordia Constel- lation provides coverage of southern latitudes through six quasicircular equatorial orbits at 8040 kilometers, and four complementary elliptical orbits to increase daytime capacity. Ellipso is a service of U.S based Mobile Communi- cations Holdings, Inc. Mobile's communications ser- vices are designed to enhance rather than displace existing phone and data services. Mobile Communi- cations is targeting low-cost services especially to isolated and rural areas. elliptic curve A geometric structure of interest to cryptographers because it can be incorporated into algorithms with calculations that can be performed 315 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary with relative ease in one direction, but that are diffi- cult or impractical to reverse thus foiling decryption efforts. ELOT Hellenic Organization for Standardization, located in Athens, Greece. ELOT handles standard- ization, certification, and quality control in Greece. http://www.elot.gr/ ELSU Ethernet LAN Service Unit. EMA See Electronic Messaging Association. EMACS, GNU EMACS A powerful, flexible, con- figurable, network-savvy text editor written originally by Richard Stallman and promoted and supported by a large community of programmers. EMACS works on a wide variety ofplatfonns, with GNU EMACS running principally on Unix systems. MicroEMACS is a popular derivative, and CygnusEd is a fast com- mercial editor with many EMACS-like characteris- tics. While EMACS has a bit of a learning curve, it has many useful capabilities not found in other edi- tors. It can work directly as a mail client, can read and write files directly over an FTP link, and can be modified and extended with LISP. See text editor. email See electronic mail. EMBARC Electronic Mail Broadcast to a Roaming Computer. A North American paging service from Motorola based on the X.400 standard. EMBARC transmits 8-bit text and binary files containing up to 1500 characters. See ERMES, SkyTel, X Series Rec- ommendations. embedded Closely contained within a bounded en- vironment. The human brain is embedded within a bony structure called the skull. A microphone and speaker are embedded within the handset ofa tele- phone. Electronic components are tightly embedded within a small appliance such as a wristwatch, hear- ing aid, or handheld computer. Optical fibers are tightly embedded within the sheathing in a fiber op- tic transmission cable. In general, in communications embedded devices are those in which electronics or transmission media are packed into a tightly constrained space. This arrange- ment was difficult in the days when electronic devices were based on vacuum tube technology. Transistors made it possible to greatly reduce the size of a de- vice and the proximity of the components within that device. Large-scale integration of semiconductors took this trend one step further, enabling microminiaturiza- tion of logic-capable devices. There are many reasons for embedding components: transmission speeds may be increased, power con- sumption may be lower, proprietary technologies may be hidden or obscured, or the footprint or size/weight of the device may be minimized. Embedded devices may also have disadvantages: fabrication may be more technical or costly, electromagnetic interference may be more prevalent, servicing may be more diffi- cult, or the space for including enough hardware and software resources to meet the task at hand may be limited. See embedded devices. embedded devices I. A general category of compo- nents that are especially useful in mobile and space systems due to their low power consumption and 316 compact size. 2. A quickly growing class of consumer devices in which the electronics are bundled into small housings to enable the production of products that are convenient and easy to power by battery sources. VLSI technology and circuit boards have made it increasingly practical to design small, sophis- ticated portable devices. Forty years ago the only embedded devices people regularly carried around were wristwatches and transistor radios. Now it is not uncommon to see a person carrying a watch, a cellu- lar phone, a pager, a GPS device, an electronic sched- uler, a garage door opener, and a calculator, all at the same time. The programming of embedded devices is aparticu- lar challenge to programmers who have become ac- customed to working on desktop computers with 128K of memory and 1600 x 1200-pixel screen dis- plays. Embedded devices often have significant memory and display area constraints, equivalent in some ways to the microcomputers of the late 1970s. Older programmers are familiar with programming text for 8K 120 x 80-pixel text displays but probably didn't expect that skill to become useful again in the year 2001. To facilitate programming for embedded consumer devices, environment emulation programs for use on desktop machines have been developed. See Java. embedded operations channel EOC. In a data trans- mission, a number of bits set aside for use for moni- toring configuration, maintenance, or other perfor- mance data that are distinct from the user data trans- mitted in the nonnal channel but carried tightly within the data stream (in-band) as opposed to being trans- mitted separately (out-of-band). EMC electromagnetic compatibility. EMC and Radio Spectrum Matters Technical Committee ERM. A working committee of the Eu- ropean Telecommunications Standards Institute (ETSI) involved in developing standards for electro- magnetic compatibility, radio spectrum, and a range of radio products (mobile, broadcast radio, vehicle transmitter systems, etc.). It's a broad mandate, be- yond the scope of any single committee, so ERM works closely with the Operational Co-ordination Group and others. Significant progress was made in conjunction with the ETSI Mobile Standards Group Technical Committee in creating Universal Mobile Telecommunications System standards during 2000 and 200 I. A Task Group was created focusing on air interface specifications, and a Guide was published to assist network operators in developing interoper- able interface specifications. ACitizen's Band (CB) Guide was also published with findings regarding the impact of CB frequencies (27 MHz) on other radio technologies. emergency access An alert system incorporated into some private branch exchange (PBX) systems that rings selected phones, or all phones, in the event of an emergency. Emergency Alert System EAS. A new emergency system designed to replace the Emergency Broad- cast System (EBS). The EAS is based upon digital © 2003 by CRC Press LLC technology, and all broadcast stations are required to have EAS decoders subsequent to January 1, 1997. The EAS provided for a one-year transition period during which old equipment had to be retained to en- sure that new equipment could take over the func- tions effectively. Furthermore, television stations must be able to automatically send a visual message. Specific equipment for delivering the emergency messages has not been defined on a physical basis. Instead, the type of message functions that must be supported are described. The equipment allocated to these functions must be certified. Live monitoring, logging, and documentation requirements form part of the EAS. See Emergency Broadcast System, Glo- bal Maritime Distress and Safety System. Emergency Alert System (EAS) activation signal A mandatory protocol of the EAS, consisting of a digital header, an attention signal, a message, and an end of message (EOM) code. The header contains in- formation about the origin of the message, its nature, location, and time during which it is valid. Emergency Broadcast System EBS. A warning sys- tem that has been replaced by the new digitally based Emergency Alert System (EAS). See Emergency Alert System, Emergency Digital Information Sys- tem/Service. emergency dialing A type of speed dialing in which a shortened sequence of numbers, or sometimes even one button, facilitates a fast connection with emer- gency telephone services such as the police, ambu- lance, or fire department. Emergency Digital Information System/Service EDIS. An emergency and disaster information ser- vice established in California in 1990 for delivering official information to the news media and the pub- lic. As such it constitutes a Community Warning Sys- tems (CWS) that supplements national disaster ser- vices such as the EAS. Due to the prevalence of earth- quakes and floods in Californian urban areas, and the proximity of many high technology companies, it seems natural that California would be one of the early adopters of an electronic disaster information service. In the late 1990s, the California EDIS sys- tem was updated to include sound and graphics and to support satellite datacast capabilities. It is now managed by the Governor's Office of Emergency Ser- vices. EDIS combines a 24-hour broadcast service, news- wire, and a Website to provide authorized agencies with emergency or disaster-related text, graphics and sounds via computer networks. It distributes mes- sages from the California OES Data Network, the Na- tional Weather Service, the Law Enforcement Tele- communications System, and a number of special- ized science networks providing seismic and other disaster-related information. Transmitters are spaced around California, particularly in the Los Angeles and San Francisco Bay areas where population densities are higher, and broadcast on standard radio frequen- cies that can be accessed by amateur radio systems. EDIS information can be accessed by the general public and the news media through digital radio broadcasts, email, maps, and images optimized for computer transmission and display. EDIS is designed to be accessible even if public networks are 'grid- locked' due to excessive demands typical of disaster situations, through its satellite distribution network. EDIS provides a means to convey Emergency Alert System (EAS) messages as well as local information to the general public and emergency and disaster re- lief agencies. http://edis.oes.ca.gov/ emergency hold A capability in which an emergency ~r~~:;~~~ ~~rfifv~i~~~~~}i~~e~~~r~:~~n~~ u~e: :. presses the switch hook. Since it is not unusual for people in emergency situations to behave erratically, or to hang up inadvertently and then try to reconnect, it gives the emergency personnel the opportunity to retain or regain contact with the caller. Emergency News Network ENN. While this title is used generically to refer to a number of different state and national news services, it is often used specifi- cally in connection with the Chicago-based EmergencyNet News, a service of the Emergency Response and Research Institute. Emergency Number Service ENS. A provision of common carriers of land and mobile telephony ser- vices for quick access to emergency services. In North America, 911 is the familiar emergency number. In other countries, there are other systems. For example, in some locales, 999 is used to call for police assis- tance. See 911 calling, E-911, National Emergency Number Association. emergency telephone A phone designed to provide service in spite of unusual circumstances, such as power outages. It may have backup batteries or a con- nection to emergency power in order to maintain op- erability. It may also have a direct wire or priority wireless connection to emergency services. EMF, emf 1. See electromotive force. 2. See Elec- tronic Media Forum. 3. See European Multimedia Forum. EMI See electromagnetic interference. emission 1. Outward radiation or conduction of waves. 2. Ejection of electrons, which could arise from avariety of causes such as impact or heat. emission currentA current produced in the plate of a cathode-ray tube (CRT) when the electrons beamed from the cathode pass into the plate. emission velocity The initial velocity of electrons beamed from the cathode in a cathode-ray tube (CRT). emissivity A measure of the ratio of flux emitted by a radiation source to the flux radiated by a black body with the same area and temperature. emitter 1. A device that provides periodic pulses at regular intervals as is used, for example, on punch card machines. 2. An electrode in a transistor (minor- ity carrier). emitter-coupled logic ECL. A fast logic-circuit am- plifier comprising a bipolar transistor pair with coupled emitters. It is one of three main logic fami- lies. ECL is faster than similar transistor-transistor logic (TTL) circuitry (with atradeoff in power to keep the circuit active); the gate delay may be less than 317 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary I ns, making it suitable for high-speed data circuits. See CMOS, transistor-transistor logic. emotieon An apt name for an online grassroots evo- lution of tiny ASCII icons to represent moods, emo- tions, and expressions. Since networks before the Web were traditionally text-based, and since commu- nications online can often be misunderstood without facial and voice expressions to express subtle distinc- tions, many users have adapted an iconography into text messages to provide a wider range of expression. Because of the difficulty of creating vertical draw- ings in a text-based message, most emoticons are designed to be read sideways, that is, with your head turned 90°, usually to the left. EMP See electromagnetic pulse. empty slot ring In a ring-based local area network (LAN) topology, such as Token-Ring, a free packet that travels around the ring through each node on the network, and is checked at each workstation for messages. EMR See Exchange Message Record. EMS See Expanded Memory Specification. EMT electrical metal tubing. EMTUG See European Manufacturing Technology Users Group. EMU I. Economic and Monetary Union. A long-term plan for the unification of Europe into a common market, resulting from the Maastricht Treaty of 1992. 2. European Monetary Union/Unit. A common mar- ket currency in effect as of I January 1999 based on measures taken by the Economic and Monetary Union. emulate To copy, simulate, provide working TImc- tions of. emulation, software To recreate the functioning of an application or operating system. Emulators abound in the computer world. There are Macintosh OS emu- lators for Amigas and NeXT computers, and Win- dows emulators for Macintosh and Amiga comput- ers, etc. It is not strictly true that an emulator always runs more slowly than the original system. With fast hardware, one operating system can sometimes run an emulator faster than the OS may run on the ma- chine for which it was originally designed. En Bane An informal Federal Communications Commission (FCC) forum for the discussion of FCC rules and policies. : -) : ) ; -) ; ) : -D :D : -0 :0 : - / : - ( :-\ : -I :-p Emoticons (Smileys) two variants of the basic smiley, the most common emoticon a smile with a wink laughter, a big talker, delight surprise, astonishment, awe smirks frowns sticking a tongue out encapsulated PostScript EPS. APostScript file for- mat including bounding box information (explicit statements about the lower left and upper right ex- tents ofa rectangular area that includes the entire im- age contained in the file). The EPS bounding box in- formation is commonly found in the header at the be- ginning of the program. Many programs cannot print a PostScript page without the EPS information, if it is an imported file, since the size and boundaries of the image may not be explicitly stated in the page de- scription code. (It's like trying to find a frame for a picture without fITst knowing the size of the picmre.) EPS is a widely supported vector format and is use- ful for desktop published documents, posters, typog- raphy, and other applications in which one wants to take advantage of the highest possible quality avail- able on aparticular output device. See PostScript. Encapsulating Security Payload ESP. In TCPIIP networks, ESP is a transport layer protocol compat- ible with both IPv4 and IPv6 formats. It operates in both tunnel mode and transport mode. In secure net- work transmissions, the ESP may be used in conjunc- tion with an authentication header mechanism. See link encryption, RFC 1827, RFC 2401. encapsulation I. Encasing or completely surround- ing with a protective covering. When something is encapsulated, there's not usually much room between the covering and that which is being covered. Encap- sulation is used for insulating, sealing, or separat- ing, and it might make the contents water- or airtight. 2. In frame relay, aprocess by which an interface de- vice inserts the protocol-specific end device frames into the frame relay frame. 3. Ameans ofwrapping a bundle of network information in order to tunnel it through a system, to pass it through different proto- cols, without altering the wrapped data. It is subse- quently de-encapsulated to retrieve the wrapped in- formation. See Point-to-Point Tunneling Protocol, tunneling. encoding The conversion of data from one form to another, sometimes to obscure the contents, some- times to reduce the amount of space necessary to hold the information, and sometimes to change it to a com- patible format. Compression and encryption are two means of data encoding. Encrypted Communications Privacy Act ECPA. An Act introduced in March 1996 to address legal security levels for computer network transmissions and civil liberties by preventing unlimited access to computer records by the U.S. Govermnent. This Act came about in part due to criticisms and concerns expressed after the enactment of the Electronic Com- munications Privacy Act of 1986 (ECPA). One of the arguments for allowing the use of higher level encryption was to aid Americans in maintain- ing safe and secure business and personal transactions in a globally connected world. Another motivation for assigning this limiting measure to govermnent came from U.S. industry assertions that the U.S. would have difficulty maintaining a competitive ad- vantage in the global marketplace with respect to en- cryption technologies (with strong export restrictions 318 © 2003 by CRC Press LLC on software, foreign nations were offering stronger encryption on competing products than the U.S. ven- dors were permitted to offer). See Electronic Com- munications Privacy Act of 1986, encryption. Encrypted Key Exchange Protocol, EKE Proto- col A password-based certificate-free protocol de- signed to increase security in digital networks. Intro- duced in the early 1990s by S. Bellovin and M. Merritt of AT&T Bell Laboratories (U.S. patent #5,241,599), it combines symmetric- and public-key cryptography to enable two parties, sharing only a relatively insecure password, to initiate a computa- tionally secure cryptographic communication over an insecure network, such as a wireless telephony sys- tem. The system provides security against passive and active attacks and dictionary-style password-guess- ing attacks. Since its introduction, extensions and adaptations of this system have been suggested, in- cluding Japan's Dual-Workfactor Encrypted Key Exchange Protocol. See Kerberos authentication. encryption The process of encoding data in a way that makes it difficult or impossible to decode. En- cryption is widely used in times of conflict to hide the contents of sensitive communications. It is also used for encoding private messages or business trans- actions and documents. Encryption is often combined with authentication. Key encryption is a type of en- coding which uses public and private keys to encode and retrieve messages. See Clipper Chip, key encryp- tion, Pretty Good Privacy. EncryptionControlProtocol ECP. A means for con- figuring and enabling data encryption algorithms on both ends of a point-to-point (PPP) link. ECP uses the same basic packet exchange mechanism as the Link Control Protocol (LCP). See RFC 1968. Encryption for the National InterestAct A House of Representatives bill (H.R. 2616) introduced in July 1999 by numerous representatives. It deals with pri- vacy and encryption but is significantly different from the Security and Freedom through Encryption Act proposed in February 1999. It supports freedoms to use encryption for domestic purposes but does not explicitly support the production, transfer, or vend- ing of encryption-related products. Encryption export restraints are discussed instead. The proposal further does not require key escrow or other access to sup- port law enforcement efforts to decrypt communica- tions related to criminal activities although it does delineate procedures to be followed for gaining ac- cess to plaintext ofdecryption information upon re- ceipt ofa court order. See E-Privacy Act, Security and Freedom through Encryption Act. end delimiter An end of file (EOF), end of block (EOB), end of line (EOL), end of message (EOM), end of transmission (EOT), or other data signal that designates the final byte or section of a block of in- formation. end device 1. The terminal point, whether it be the source or the destination, ofa data transmission. 2. A hardware or software terminal device, which may be a file server or host. 3. In a frame relay network, data is sent from the source to an interface in which it is encapsulated irito a frame relay frame. At the desti- nation end device, the frame relay frame is stripped off again (de-encapsulated). See Data Communica- tions Equipment, Data Terminal Equipment. End Office switches Hardware routing switches from which telecom subscriber Exchange Services are connected. These may be private branch trunks and their connections with Interexchange Carriers or Competitive Local Exchange Companies. Local End Office switches may be designated as Class 5 switches. Some systems use a combination of Class 4 (e.g., long-distance Tandem switches) and Class 5. The trend is for telephony and data services to be car- ried seamlessly over the same infrastructure. Digital End Office switches are gradually supersed- ing traditional analog switches, and various issues related to their function (e.g., trunk group echo) have resulted in changes and upgrades in End Office switches. Next Generation switches may be installed as alternatives to certain End Office switches. One of the most recent developments is the implementa- tion of software-based Class 4 and 5 switches (Softswitches) that enable a telecommunications ser- vice provider with broadband access to offer reduced- cost services or End Office functions. See Exchange Service. end to end digital path Acommunications link be- tween two hosts capable of sending wholly digital data (without analog conversion along the way) over an arbitrary number of routers and subnets. endtoend path A communications link: between two hosts capable of sending data over an arbitrary num- ber of routers and subnets. end to end service A network service that links one subscriber to another subscriber or another branch of the first subscriber. It typically consists of the local loops at each end of the transmission connected through an InterExchange Carrier (IXC). end user 1. The service or product user at the end of the retail or service chain; in other words, it's not a user who is a wholesaler, broker, or agent. Some people use this phrase interchangeably with user, but it might be useful to maintain a distinction. 2. In tele- phone services, an end user is distinguished as a sub- scriber using loop start or ISDN. 3. In network com- munications, the computer users who are not the tech- nical administrators of the system, e.g., students and faculty on a college campus. endface A planar surface of a component, wire or cable. On a cable, it is the terminating surface more or less perpendicular to the length of the cable, which is attached to couplers, components, and other cables. endface testIn fiber optics fusing processes, inspec- tion of the end surfaces of cleaved fiber optics fila- ments. The ends must meet certain specifications for smoothness and cut angle tolerances so the surface lets light pass readily and evenly rather than being distorted or reflected back into the originating fiber. endoscope A medical exploratory instrument for re- motely viewing inside-body structures. The endo- scope was one of the first instruments to use glass fibers, in the early 1900s. In 1952, Harold H. Hopkins 319 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary applied for a grant from the Royal Society to develop glass fiber bundles into an instrument for endoscopic viewing. When the grant was approved, Narinder S. Kapany, a significant pioneer in fiber optics, was brought in as an assistant. Fiber-based endoscopy enables surgeons to view the interior of the body through smaller incisions, reducing the possibility of infection and speeding surgical recovery. EnergySciences network ESnet. The network of the U.S. Department of Energy chartered in 1986 as a result of combining MFEnet, which had operated since 1976, and HEPnet, a leased-line network estab- lished in 1980. In the early 1990s, ESnet began to offer international data services and implemented World Wide Web connectivity. In 1996, the ESnet base was relocated to Lawrence Berkeley National Laboratory. ESnet provides a high-end, advanced, reliable communications infrastructure to support the Department of Energy's scientific research and vari- ous projects. http://www.es.net/ Englebart,Douglas (1925- ) An American innova- tor and engineer who served as a radar technician in World War II and subsequently joined the NASA Ames Laboratory. He later had the opportunity to pursue some of his pioneering ideas at the NLS labo- ratory at the Stanford Research Institute in the 1960s and at Xerox PARC in the 1970s. Englebart is cred- ited with inventing the three-button mouse in the late 1960s, an accompanying keyset, and many of the graphical user interface ideas that are now prevalent on desktop computers. His concept of "windows" as a means of expressing a work area on a computer monitor was further enhanced by Alan Kay, the origi- nator of Smalltalk, and others in the lab at the time. Englebart has many patents. See Kay, Alan. enhanced-defmition television, enhanced-defini- tion TV EDTV. A general category of television tech- nologies that forms a bridge between traditional NTSC technologies and advanced television (ATV) technologies. EDTV is a means to improve analog NTSC broadcasting without going to an entirely new system (e.g., digital technologies). Thus, enhanced signals within the existing broadcast channel or added signals provided through additional spectrum alloca- tions can augment existing broadcast technologies. See advanced television. EnhancedCall Processing ECP. A subscriber phone service with enhanced voice mailbox features that allow more than one user on the line to have an indi- vidual mailbox or for mailboxes to be individually configured to be listen-only, redirect, menu-directed, or leave-a-message. Commonly the ECP can be pro- grammed through online menus, greatly enhancing applications that can be established on the system. ECP services can also be established through voice/ fax modems by configuring the software on a com- puter. Thus, fax-back, voice mailbox, redirect, and other applications can be programmed to control the modem. The modem, in tum, handles the manage- ment of the phone line. EnhancedDigitalAccess Communications System EDACS. A widely distributed commercial, trunked, 320 public safety mobile radio communications system from Ericsson Inc.lGeneral Electric. EDACS oper- ates in 800-MHz, 900-MHz, VHF, and UHF fre- quency bands and is utilized by private firms, public safety organizations (police departments, airports, and the u.S. Naval District in Washington, D.C.). The system is hierarchical, with talk groups organized into agencies, which are further divided into fleets and subfleets. Each radio frequency is assigned a Logi- cal Channel Number (LCN) that is programmed into each radio on the EDACS system. Dual-format mo- bile radios from Ericsson/General Electric can be used on EDACS systems. Enhanced Graphics Adapter EGA. A 16-color graphics display standard developed to supersede the Color Graphics Adapter (CGA) standard that was prevalent on Intel-based desktop computers in the mid-1980s. EGA could display up to 640 x 350 pix- els. It has since been superseded frrst by Video Graph- ics Array (VGA) and then Super Video Graphics Ar- ray (SVGA) formats which offer higher resolutions. Part of the reason for improved graphics resolutions stemmed from competitive pressure from a large nwn- ber of color graphics systems released in the 1980s by vendors supporting the Motorola 680xx chipset rather than the Intel chipset. The Apple IIGS, Commodore Amiga, Silicon Graphics workstations, and Atari ST all had high resolution graphics with thousands or millions of colors while most Intel/MS-DOS-based systems at the time were still displaying 16 colors (8 regular colors plus 8half intensity). See Color Graph- ics Adapter, Video Graphics Array, Super Video Graphics Array. Enhanced Group Call EGC. Broadcast messaging and routing services commonly used in safety and warning systems such as Inmarsat mobile satellite communications. For example, EGC facilities are part of the International SafetyNET maritime safety sys- tem. They are also incorporated into the FleetNET broadcast facility, which enables the simultaneous transmission ofa single message from an authorized information provider to multiple Inmarsat-C Ship Earth Stations (SESs). Typically, an EGC message is identified by an EGC network identification code (ENIC) that may be stored in the Ship Earth Stations system. The mes- sage to be sent includes an address specifying the geographic region for the destination. The message may be sent to individuals, specified groups, or all receivers within the specified network. Multiple re- cipients receive the message at about the same time. Commercial EGC receivers enable ship positions to be entered and updated manually and automatically. They may be combined with Global Positioning Ser- vice receivers in integrated units. Enhanced IDE An enhanced computer peripheral device controller specification that provides faster transfer speeds and larger addressing space than the original IDE specification. See IDE devices and con- trollers. Enhanced Parallel Port EPP. A parallel data trans- missions specification intended to provide faster © 2003 by CRC Press LLC parallel speeds over common desktop computer par- allel ports, without changing the basic hardware (cables, connectors, etc.) used to implement the con- nection. Parallel ports are commonly used with im- pact printers and some inkjet and bubble-jet printers. Etherne~ USB, and Firewire formats may eventually supersede EPP for desktop peripheral connections. Enhanced Position Location Reporting System EPLRS. A digital, mobile, tactical radio system used by the U.S. military to provide an integrated network to support high-speed, automated warfighting sys- tems and to enhance command-control capabilities. It also serves as a communications backbone for the military's Tactical Internet. ELPRS enables the col- lection of data from widely dispersed systems in battle areas, transmitting them back to command cen- ters and combat force locations. Each radio in the military network is assigned a unique identifier and unique time slots during which it can transmit to the Net Control Station (NCS) and other radio sets using time division multiple access (TDMA). Automated functions enable EPLRSs to avoid jam- ming threats and to adjust to and overcome line-of- sight changes and limitations. The Raytheon EPLRS operates in wi deb and UHF frequencies using embed- ded cryptography for security at variable data rates up to 100 Kbps. In actual practice, U.S. military sys- tems transmit at up to about 56 Kbps, but higher rates are expected with the integration of military and com- mercial systems in future upgrades. See Enhanced Trivial FTP. Enhanced Serial Interface ESI. A freely distributed serial interface specification developed by Hayes Microcomputer Products. It is an extension to the COM Card specification for desktop computers. Enhanced Serial Port ESP. A Hayes serial port specification introduced in the early 1990s that is in- tended to extend and replace the COMI/COM2 ports that are familiar to most users of Intel-based desktop computers. It provides two independent operations modes, to support existing standards and the ESP for- mat. Depending on the version, defaults are set ei- ther with the Hayes Programmable Option Selection (PaS) or with DIP switches. Enhanced Service Provider ESP. Acategory of ser- vice provider recognized by the Federal Communi- cations Commission (FCC) as subject to certain rules, regulations, and exemptions. As digital phone services and data communications services became more prevalent in the 1980s with the increased use of computer modems and computer networks, the FCC needed to sort out how the regu- lations governing telephone services and interstate commerce should apply or be changed to apply to developing computer timeshare and digital service providers. Should enhanced phone service companies and computer bulletin board sysops be regulated as common carriers? This question led to a distinction between (1) basic telecommunications services, fo- cusing on the physical transmissions capability and (2) enhanced services, encompassing everything beyond the basic physical transmissions capability. Thus, voicemail services, computer bulletin board systems, Internet access services, document transmis- sions services, etc. came within the category of en- hanced services, and those who provided them were distinguished as Enhanced Service Providers (ESPs). In 1983, the FCC determined that ESPs would be exempt from access charges related to interexchange service, even though phone lines were being used to implement data communications services. While ad- justments and changes have occurred since that time, including close scrutiny in December 1996 through the Access Charge Reform proceeding, the general concept to promote the competitive viability ofESPs continues to receive support. See ASP Industry Con- sortium, Telecommunications Act of 1996. Enhanced SpecializedMobile Radio ESMR. A tra- ditional nationwide wireless two-way radio dispatch service that has been expanded to offer services some- what similar to cellular, but with more limited allo- cation of bandwidth in the 800 and 900 MHz regions. The technology began to catch on in the late 1990s, evolving from the well-established SMR radio net- works. ESMR uses the same frequency band as SMR but uses newer digital technologies to increase capac- ity and the range of services over awider geographic area. A single switching center may support 500 or more base transceiver stations (BTSs). To cost effec- tively support this many BTSs, they may be organized into small groupings (hubs) with each group con- nected, in tum, to intermediate stations. In this way, multiple circuits can share the resources ofa fast digi- tal transmissions medium (e.g., a T1 line). The ESMR system is currently adding millions of new subscribers per year. More recent implementa- tions of the technology go beyond traditional dis- patch, offering digital two-way radio, cellular phone services, and packet-data services (within the general dispatch-related niche) within areas licensed to ESMR vendors. The technology is now being ex- tended by commercial vendors (e.g., Motorola) to create virtual private networks for workgroups within the framework of the larger ESMR system. ESMR services are ofparticular interest to utilities, construc- tion, sales, and transportation (bus, taxi, trucking) in- dustries. In Europe, ESMR is based on Terrestrial Trunked Radio (TETRA) standards (ETSI). See iDEN. enhanced T~ enhanced Television A general cat- egory ofbroadcast technologies similar to traditional TV but characterized by additional services, which may include subtitles, closed captioning, on-demand viewing, and other enhancements arising from digi- tal broadcasting and Internet communications. Two- way communications are necessary for many en- hanced TV services and broadcast triggers are used to administrate the recognition and delivery of enhanced services. The basic data categories supplied through enhanced TV are announcements, content, and broadcast data triggers. Announcements provide the user with op- tions, services, annotations, or scheduling information 321 © 2003 by CRC Press LLC . system, to pass it through different proto- cols, without altering the wrapped data. It is subse- quently de-encapsulated to retrieve the wrapped in- formation. See Point-to-Point Tunneling Protocol, tunneling. encoding The conversion. a component, wire or cable. On a cable, it is the terminating surface more or less perpendicular to the length of the cable, which is attached to couplers, components, and other cables. endface testIn fiber optics fusing processes, inspec- tion of the end surfaces of cleaved fiber optics fila- ments. The ends must meet certain specifications for smoothness and cut angle tolerances so the surface lets light pass readily and evenly rather than being distorted or reflected back into the originating fiber. endoscope. Processing ECP. A subscriber phone service with enhanced voice mailbox features that allow more than one user on the line to have an indi- vidual mailbox or for mailboxes to be individually configured to be listen-only, redirect, menu-directed, or leave-a-message. Commonly the ECP can be pro- grammed through online menus, greatly enhancing applications that can be established on the system. ECP services can also be established through voice/ fax modems by configuring the software on a com- puter. Thus, fax-back, voice mailbox, redirect, and other applications can be programmed to control the modem. The modem, in tum, handles the manage- ment of the phone line. EnhancedDigitalAccess