Fiber Optics Illustrated Dictionary - Part 83 pdf

Fiber Optics Illustrated Dictionary Research and Education R&E. Those served by the National Science Foundation's (NSF) networking efforts. Research in Advanced Communications in Eu- rope RACE, RACE II. Also known as Research and Development in Advanced Communications Tech- nologies in Europe and R&D in Advanced Commu- nications Technologies in Europe, this program be- gan with work by the RACE Management Commit- tee that was tendered to the European Community Council and became the predecessor to the later Ad- vanced Communications Technologies and Services (ACTS). RACE was organized in the mid-1980s to aid in the EC-wide establishment and unification of communications systems and providers. Following a definition stage, the RACE projects were carried out between 1987 and 1995 with financial contribu- tions from the EC. Over the period of its tenure, more than 350 organizations participated in RACE projects and RACE collaborated with many important orga- nizations, including ETSI, EFTA, EUREKA, ES- PRIT, and others. In the early and mid-1990s, RACE was involved in the research and development of telecommunications technologies leading to the development of the Inte- grated Broadband Communications (IBC) system and more specifically the Mobile Broadband System (MBS). With its evolution to ACTS, the third phase ofIBC development continued the work beyond the original 5-year mandate of the RACE projects. See Integrated Broadband Communications, Mobile Broadband System. Research Institute for Advanced Computer Sci- ence RIACS. A research facility located at the NASA/ Ames Research Center in California. In conjunction with the NASA/Ames center, RIACs sponsors a Sum- mer Student Research Program (SSRP) to provide students with the opportunity to team with research professionals in Moffet Field. Topics include auto- mated reasoning, high-performance computing and networking, and applied research for NASA mis- sions. Research Laboratory ofElectronics RLE. The first interdisciplinary research lab established at the Mas- sachusetts Institute of Technology (MIT). The RLE, founded in 1946, is descended from the MIT Radia- tion Laboratory, which provided some significant discoveries during World War II. RLE brings together expertise from many quarters, including electrical engineering, physics, computer science, chemistry, aeronautics, linguistics, and others. The facility is primarily supported by the U.S. Department of De- fense (DoD), the Department of Energy (DOE), and several national institutes and foundations (NASA, NSF). Reseaux Associes pour la Recherche Europeenne RARE. A European research network that was merged with EARN in 1994 to form TERENA. A number of technical reports were published by the RARE Working Group prior to the merger. See TERENA. resellerA company which purchases a block of services 812 (e.g., long-distance services) or numbers (e.g., cel- lular phone numbers) and resells them directly to cus- tomers. The reseller does not own and usually does not maintain the physical structures or services, but usually provides information and technical support to the resale customers. See agent, aggregator. reset v. Return to the previous or default or factory operating settings. In computer operating systems, a reset command usually restores the system to the same configuration (or nearly so) as a fresh power- up, although some will restore memory, parameters, etc. without resetting some of the basic subsystems (e.g., sound). Asoftware reset that doesn't involve a . power-down is termed a"warm boot" and acomplete power-dOwn is called a"cold boot." Ifasoftware re- set doesn't seem to correct problems, it's best to do a cold boot. But wait at least 15 seconds for the power to drain from the chips before powering up again. In timing mechanisms or data counters, a reset usu- ally restores the time or counting mechanism to a zero condition or industry default. Residential Broadband RBB. A broad term for higher capacity/higher speed broadcast and network- ing services to residences. Larger providers such as NTT and AT&T are already engaged in upgrading cables and services to provider agreater range of pro- gramming choices to home subscribers. New switch- ing technologies are an important technological and economic component of these upgraded services. See fiber to the home. Residential Broadband working group RBWG. A working group of the ATM Forum Technical Com- mittee which promotes a single set of global specifi- cations to maximize interoperability of products from various vendors. The Residential Broadband group provides documents and recommendations regarding enhanced services to residential users of ATM-related technologies. Residential Enhanced Service RES. A telephone subscriber service package offered by Nortel that in- cludes enhancements such as increased security and features such as Call Redirect. resinous electricityAhistoric term coined by Dufay to denote the type of electrostatic charge produced on sealing wax when rubbed with flannel (or amber rubbed with wool). Later, in the 1700s, Benjamin Franklin proposed negative, a term that superseded vitreous. See electrostatic, static electricity, vitreous electricity. resistance I. Opposition, counteracting force or re- tarding force against. 2. In electricity, opposition to the flow ofcurrent, usually expressed in ohms. There is great variability in the resistance of various mate- rials. Those with low resistance, such as silver and copper, make good conductors. Resistance in a par- ticular material may change with temperature, mois- ture, or the presence or absence of current. Resistance is defined as the reciprocal ofconductance. See re- luctance, resistor, ohm. Contrast with conductance. resistor A component or system which provides re- sistance to electrical current. Some materials are natu- rally resistant, and this property may be further © 2003 by CRC Press LLC exploited by the way a circuit is configured (e.g., longer wires, more loops, etc.). Controlled current is useful in a number ofcircumstances and can be used to protect sensitive components or to provide opera- tional control. Electronic resistors use standard color coding schemes to identify the degree ofresistance they provide. Applying Ohm's law, it can be stated that the combined resistance of any two resistors con- nected in parallel can be expressed by dividing their product by their sum. See Ohm's law, resistance. resolution Resolution is somewhat technology-spe- cific, since it is often based not only on the size or discrete value of an individual unit, but also on the total area occupied by a block or line of units, and the units will vary depending upon the type of me- dium or technology described. resonance 1. The enrichment of a sound by supple- mentaIy vibration. For example, the body of an acous- tical stringed instrument is designed to increase the resonance of the string vibration by transmitting the sound through the bridge, the sound holes, and the body. 2. A greater amplitude vibration arising from smaller periodic vibrations with the same, or nearly the same, period as the natural vibration period of the system. This can arise in both electrical and mechani- cal systems. 3. The enhancement of an event by cre- ating excitation within the system, as in particle re- actions. See magnetic resonance imaging. 4. In a cir- cuit, a balanced condition between inductive- and capacitive-reactance components. resonance curve A diagrammatic representation of the relationship of various frequencies at or near reso- nance to a tuned circuit. resonance Raman scattering See Raman scattering. resonant frequency The frequency at which a maxi- mum amplitude response occurs in a given object or system when acted upon by a constant amplitude si- nusoidal force. In an antenna, for example, the trans- mitting current is greatest when the impedance level is lowest at a given frequency and power. resonator 1. A device which increases and/or directs sound, as in a musical instrument, music box, or tele- graphic sounder. In gramophones, a hom which am- plifies and directs sound to the listener. 2. In tele- graphic systems, a box which holds a sounder and directs the audible clicks to the ear of the operator. 3. In microwave communications, a hollow, metallic container in which microwaves are produced and amplified. 4. In crystal detectors, apiezoelectric crys- tal which oscillates when stimulated by radio waves. resonator, optical Amechanism to reflect and am- plify radiant energy in the optical frequencies through resonance patterns set up among the interacting re- flected waves. An infrared resonating chamber was described in a 1956 patent application by R. Dicke. Optical resonators were described more fully by G. Fox and T. Li and by G. Boyd and J.P. Gordon, in 1961. Based upon a Fabry-Perot interferometer as a resonating mechanism for optical masers (pioneer lasers), Fox and Li described a resonating system in which the reflecting mirrors of the interferometers reflected the optical beam back and forth until, after many reflections, the relative field distribution was "synched" and the amplitude decayed exponentially. The difference between the oscillating maser and ear- lier masers was that the lowest-order mode could be made to dominate given the correct spacing, relative to frequency, for the resonance. Resonance chambers or external Littman-Metcalf resonating cavities are now intrinsic to traditional la- sers, laser diodes, and other electromagnetic devices that benefit from signal amplification. resonator, unstable A resonating mechanism in which the relationship of the radiant energy and the chamber is such that the signal becomes unstable, that is, it progressively moves off the primary axis be- tween the reflecting surfaces. This may be due to the character of the radiant energy source, fluctuating or incorrect power levels, the relationship of the reflect- ing mirrors to one another and/or to the beam, or flaws in the general assembly or components. It may also be a deliberate compromise between fabrication dif- ficulty or expense and the level of signal' needed to accomplish aparticular task. (An unstable signal will eventually escape through the reflective surfaces or through a hole in the resonating cavity.) In most cases, instability is an undesired quality. However, unstable resonation also has some particu- lar characteristics that were described in the 1960s that may be exploited for certain purposes. By the early 1980s, unstable resonation was being incorpo- rated into specialized commercial solid state lasers. Later, hybrid stable/unstable systems began to appear. The use of deformable mirrors in solid state hybrid lasers makes it possible to decrease diffraction influ- ences on the focused beam. More recently the diffraction properties of unstable lasers were found to be the source ofsurprising frac- tals as the resonating cavity spilled out around reflect- ing surfaces and formed aesthetically interesting in- terference patterns. See Q factor, Q- factor. Resource Location Protocol RLP. A network pro- tocol to assist in the location ofa network resource in situations where other methods may not be practi- cal. This was submitted as an RFC by M. Accetta in 1983. RLP uses arequest/reply procedure to request an IP number or appropriate identifier. As an example, RLP can name a resource by an assigned protocol number and avariable-length protocoVresource-spe- cific identifier. See RFC 887. Resource Management RM. In an ATM system, cells contain information for managing bandwidth, buffers, and flow control aspects such as loads, traf- fic congestion, etc. These resource management (RM) cells are thus associated with the administration of the data transmissions. They are passed along the path through various switches to monitor and control con- gestion by adjusting the various cell rates (current, explicit, minimum) as needed. See cell rate. response time 1. The time it takes to react appropri- ately to a given situation or signal. In business, re- sponse time to customer inquiries is often critical in making sales and getting repeat business. The response time to aphone call usually needs to be four rings or 813 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary less in a business environment, or eight rings or less in a residential environment, or the caller may give up and terminate the call before it is answered. In computer operations, response time of an input de- vice, or the software, is important in terms of pro- ductivity and user satisfaction. 2. A command called ping can be used in network testing and management to determine a response time, or whether a host is even available to respond. See ping. restart 1. Initiate again, begin again. Put back into service or operation, to power up again. 2. In com- puter operating systems, to reinstate operations with- out having to power down and power up the entire system. Many computers have a key sequence, menu selection, or restart button which will reinitialize the operating parameters without a full power up se- quence. In some systems (e.g., Macintosh), the re- start option will also do a clean shutdown of the sys- tem in order to ensure that files and applications are closed, and important processes finished so no data corruption occurs from a sudden shutdown. See re- boot. restore 1. To put back to its previous or original state, to renew, revive, to return to good operating order. 2. To return to the original position, location, or owner, to re-establish, to reinstitute service. 3. To get back data which have been erased or damaged, either by rebuilding or relinking pointers, file tables, and di- rectory tables on the storage medium, or by access- ing a backup archive of the data as they were last saved. 4. In programming, to return the value of a variable to a previous value, which may be a default or original value. 5. To recharge or refresh informa- tion in a memory circuit with continuous or periodic current. Lithium batteries are sometimes used for this purpose. 6. A gadget on the edge of the windows of most operating systems with graphical user interfaces (Gills) which allows the window to be automatically sized to its original size without the user having to remember the setting or do it manually. Restricted Numeric Exchange See RNX. Restricted Radiotelephone Operator Permit RP. A fee-based permit granted without examination by the Federal Communications Commission (FCC) for the operation of most aeronautical and ground radio- telephone stations aboard pleasure craft (with some restrictions). The permit also covers the operation, repair, and maintenance of AM, FM, television, or international broadcast stations. See Marine Radio Operator Permit. Reticular Agent Definition Language RADL. An object-oriented language distributed by Reticular Systems, Inc. to facilitate the development ofintelli- gent software agents. RAnL is an extension upon work by Shoham (AGENT-O) and Thomas (PLACA - Planning Communicating Agents). Reticular Sys- tems also provides AgentBuilder, graphical tools for developing RAnL programs. AgentBuilder can pro- vide support for Knowledge Query and Manipulation Language (KQML), which can be used to share knowledge among multiple intelligent systems. AgentBuilder Enterprise supports realtime examina- 814 tion of remote agent operation, a Role Editor for defining agent roles, mobile agent support, CORBA/ DCOM support, and an enhanced repository manager. See Knowledge Query and Manipulation Language. Reticule Examples Reticules are grids, scales, or roles intended to fa- cilitate testing, calibration, assessment, or counting, especiallyfor microscope assemblies. They are typi- cally imaged on transparent glass or plastic so they can be readily superimposed over an image and may include numeric references. In microscopes, they are usually made of glass and placed close to the image with which they are compared. reticule, reticle An arrangement of rules, grid lines, dots, or wires serving as reference marks. Most of- ten, reticules are printed on transparent materials so that they may be superimposed over a field of view but it is the nature of the marks and their use as a ref- erence more than the fabrication materials that con- stitutes the reticule. It may also be imprinted on opaque materials. A reticule facilitates measuring, counting, and aligning an instrument, or viewed specimen. While most reticules are placed parallel to the view- ing plane and perpendicular to the viewing angle, a tilt reticule may aid in assessing angular deviations from a reference plane. In microscopy, areticule may be used for calibration and counting, or a micrometer may be used for cali- bration, followed by a reticule for counting. A reti- cule may be incorporated into an eyepiece (e.g., on the field stop ofa microscope) or may be used in a work or staging area (e.g., over amicroscope slide). While many reticules are preprinted, some are cre- ated dynamically as specimens are observed with only simple registration marks preprinted for align- ment (usually on the outer perimeter). In telescopy, this type ofreticule is handy as areference for chart- ing star movements. Star positions can be recorded on separate telescopes and separate reticules over time and assembled three-dimensionally to provide a map of the universe as seen from a number of view- ing angles. This type ofobservation has led to a bet- ter understanding of the "shape" of space and the dis- covery of new celestial bodies. Reticules are also used in autocollimators - devices that align a radiant energy source (e.g., a laser light source for a fiber optic lightguide) by projecting an image ofareticule that is reflected back to provide a © 2003 by CRC Press LLC basis for comparison. If there are differences between the original reticule image and the returned image that are outside of acceptable working parameters, the device makes adjustments as necessary or signals that there is a problem. The name may derive from the word used to describe a woman's small mesh or ornately beaded drawstring purse. The term is used more often in associated with assessing real objects as viewed through scientific instruments as opposed to viewing video, photo- graphic, or cartographic images, in which case the tenn graticule is more often used. See collimator, graticule. RETMA Radio Electronics Television Manufactur- ers Association. See Electronic Industries Alliance. retransmission consent In television cable broad- casting, consent is a local TV station's right to nego- tiate fees associated with program provision. It is common for a local station to purchase a variety of television programming from various distributors and broadcasters. They then resell these programs in vari- ous packages to local cable subscribers. See cable access, Cable Act. retrofit n. To equip a device or system with new parts or capabilities that were not available, or perhaps not requested, at the time ofinitial purchase and instal- lation. For example, it is very common for computer parts retailers to offer accelerator cards, storage de- vice controllers, faster CPUs, and other enhancements to users trying to upgrade or extend the life of their systems. retry Another attempt to perform the same operation if the previous attempt failed. This is an intrinsic part of most computing processes. Ifa process fails to read or write data from or to a storage location, it will re- try a certain number of times before alerting the user that there is a problem. Ifa modem fails to connect, it may redial a specified number of times before sig- naling an error condition. If a network mail server sends email to a recipient who can't be found, it may try several times before bouncing the email back to the sender. For many operating systems, the retry pa- rameters are set by programmers and are transparent to the user and not changeable. For individual appli- cations programs, there may be user preferences for retries for various operations to be controlled. return CR. A common designation for the carriage return key on a keyboard (sometimes called the en- ter key) or carriage return function in a program such as a word processing program. On most systems, the carriage return incorporates not just a return (which returns the cursor to the far left or right of the screen, depending upon the language), but also a new line (which drops the cursor down to the next line). return autborization, return mercbandise autho- rization RA, RMA. Permission from a manufacturer or vendor for a consumer or dealer to return a prod- uct, usually because it is defective, damaged, or does not meet the advertised specifications. Few vendors will process a return without prior authorization. Authorization is usually identified with a return au- thorization (RA) number. The RA is used for internal database tracking and inventory control. return authorization number RAN. A number as- signed to products returned to the vendor or manu- facturer. The number documents that the return was authorized and provides a number for tracking and stock-handling purposes once the product has been received at the return point. return loss A measure of the ratio of incoming to outgoing power, usually expressed in decibels, at a specified reference point. Return loss is a diagnostic means of evaluating various factors such as loss, qual- ity, echo, etc. return material authorization RMA. See return authorization. REV reverse. ReverseAddress Resolution Protocol RARP. A cli- ent/server tool for reporting an Internet Protocol (IP) address to its client. The protocol is intended for workstations to dynamically determine protocol ad- dresses when only the hardware address is known. The Ethernet address is mapped to the logical IP ad- dress. Used in Tep/IP. See RFC 903. reverse bias See back bias. reverse engineeringA process of working backward from a finished product or process to determine the steps taken to construct it. Thus, a clock can be taken apart to see what makes it tick, and a software pro- gram can be taken apart to see what algorithms and conditional relationships were used in its construc- tion. Software developers are generally nervous about having their software reverse engineered, because it is difficult to prove reverse engineering in cases of theft ofintellectual property. reversing error, reversal error A condition in which current divided through two circuits, such as through a component and a measuring instrument, will vary due to the deflection of the measuring instrument for the same current passing in both directions. See shunt- ing error. revision control system RCS. A system for manag- ing, queuing, and logging revisions. This is impor- tant when designing a device or protocol, or creating a document (e.g., a software manual) and is especially relevant for quality assurance and projects with more than one contributor. There are both manual and com- puterized revision control systems. A simple example is a bulletin board posting to inform the people in- volved in a revision process. Revision control is increasingly being built into soft- ware systems in factories and offices. There are au- tomation systems that will keep track of changes in a manufacturing or packaging process to prevent errors and provide an audit trail. There are word processors that will log changes by individual editors with sym- bols or colors, as well as automatically date/time- stamp the changes, so that the process is documented and the changes can be traced backward, or the indi- vidual responsible for particular changes can be iden- tified. Software designed for workgroups often has revision control features that prevent different contributors from changing a document at the same time and may notify members ofa workgroup whenever 815 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary new revisions occur. RF 1. See radio frequency. 2. range finder. A device for determining distance (and sometimes also direc- tion). See radar. 3. raster file. See raster. 4. rating fac- tor. RFA 1. See remote file access. 2. request for action. RFC 1. See Request for Comments. 2. required for compliance. RFD See Request for Discussion. RFF raster file format. See raster. RFI 1. Radio France International. 2. radio frequency interference. Electrical noise resulting from some wire or attachment acting as an antenna. 3. See Re- quest for Information. RFP See Request for Proposal. RFQ See Request for Quote. RFS 1. radio frequency shift. Unintentional drift or intentional shift (change) ofa broadcasted radio fre- quency. This may be done for security purposes or to maximize the availability of bandwidth. See fre- quency hopping. 2. radio frequency system. 3. range finding system. 4. remote file sharing/system. RG-58U A type of thin-wire cable used in 10Base-2 data communications cabling installations. RGB red, green, blue. An abbreviation to describe the three primary colors of an additive (light-based) color model. This is the model used in most computer video display devices. The colors in the spectrum are created by systematically manipulating the amount of red, green, or blue that can be individually stimu- lated. In many computer software application pal- ettes, the absence of any R, G, or B color is desig- nated as 0 and the full intensity (ofa transistor or cath- ode-ray tube gun) is designated as 255, with other colors created by mixing intermediate values. Thus, purple is created by mixing red and blue and white is created by displaying all three colors at full intensity. RGP raster graphics processor. See raster. RGS radio guidance system. Rhealstone A type of computer processing system benchmark used in realtime multitasking systems. Run times for a set of operations (task switching, in- terrupt latency, etc.) are independently measured. See benchmark, Whetstone, Dhrystone. rheostatA device with one fixed terminal and a mov- able contact, used to regulate a current by varying the resistances. Similar to a potentiometer, except that a potentiometer can connect to both ends of the resis- tance-varying element. See potentiometer. Rhumbatron Oscillator An apparent misspelling widely disseminated on the Internet for Russell Varian's Rumbatron Oscillator, mentioned here to help the reader find the cross-reference. In Varian's original handwritten note of July 1937, he called it a Rumbatron Oscillator (at least in this instance). It's an important forerunner to the linear accelerator. See rumbatron, Klystron. Riad computer A type of ffiM System/360 series- compatible computer developed in Russia. RI 1. radio interference. See attenuation, jitter, noise. 2. Rockwell International. RIAA See Recording Industry Association of 816 America. RIACS See Research Institute for Advanced Com- puter Science. RIAS See Research Institute for Advanced Studies. RIB 1. See RenderMAN Interface Bytestream. 2. See routing information base. ribbon cable A cable design in which the wires are encased so they are aligned side by side, in close prox- imity with insulating material separating the wires and holding the whole structure together like a long strip of ribbon. Typical ribbon cables carry between 9 and 60 wires. Ribbon cables are commonly used for parallel wiring connections, disk drives, and other data transfer applications, although some types of rib- bon cables carry AC power. Ribbon cables are some- what more fragile than other types of more heavily shielded cables and kinks in the cables can snap the conductors, if they are very fine. Wide ribbon cables can be difficult to attach to other types of connectors. Nevertheless, they are convenient to use in a number of places (inside computers and under floor cover- ings) because they are flat and flexible. Flat "Ribbon" Cables Examples o/two ribbon cables: the top 34 pins, the bottom 50pins. Theflatflexible cables are commonly usedinside computers where space is limitedandnar- rolv. Several devices, such as hard drives and CD- ROM drives, can be daisy-chained on one length of cable by inserting connectors that pierce the cables and make contact with the wires. RIC regional information center. Rice computer The Rice Computer Project was in- spired by the MANIAC II at Los Alamos. Three pro- fessors, Zevi Salsburg, John Kilpatrick, and Larry Biedenham, initiated the project, which culminated in the development ofa computer for research, and research into the development of computers. Joe Bighorse, as head technician, implemented most of the hardware design. The computer came online in 1959 and was fully functional by 1961. For almost a decade it was the primary computing machine on the Rice campus. Architecturally, the Rice 1 (RI) was descended from the Brookhaven computer and the MANIAC II. It was essentially a tagged-architecture computer, using 54-bit vacuum tubes plus two tag bits and seven error-correcting bits. It implemented indi- rect addressing capabilities and memory was stored © 2003 by CRC Press LLC The right-hand rule is a visual mnemonic device for remembering the relationship of the direction of the current in an electromagneticfield. Rijndael A block cipher data securing system de- signed by Joan Daemen and Vincent Rijmen selected by the U.S. Government for its Advanced Encryption Standard (AES). Rijndael has variable block and key lengths and has been specified for keys of 128, 192, or 256 bits in length. It can be implemented on a va- riety of processors. Rijndael was based, in part, upon concepts developed by Daemen and Rijmen for the Square block cipher. See RC6, Square. RIN See relative intensity noise. ring 1. The sound made by a phone or other commu- nications device to indicate an incoming call or im- minent announcement (as on a PA system). The frequency of the tone and its cadence vary from coun- try to country. In North America, phones typically ring once every 6 seconds. 2. Traditionally the red wire in a two-wire telephone circuit. The name origi- nates from the configuration ofa manual phone jack in an old telephone switchboard in which the large plug was divided into two sections, with an internal - -5 Right-Hand Rule for Current Direction N RIF See rate increase factor. RIFF 1. raster image file format. See raster. 2. Re- source Interchange File Format. A platform-indepen- dent multimedia specification developed in the early 1990s by a group of vendors including Microsoft Corporation. RIG related interest group. See Birds ofa Feather. right-hand rule, Fleming's rule A handy memory aid widely used in mathematics and physics to de- termine an axis of rotation or direction of magnetic flow in a current. Extend the thumb and fingers of the right hand so that the fingers are held together and point straight in one direction, with the thumb at a right angle to the fingers, in an 'L' shape. Now curl the fingers around a conductive wire, so that the thumb points in the direction of the current. The di- rection of the curled fingers then indicates the direc- tion of the magnetic field associated with the current. U sing the same hand relationship, point the thumb in the direction of wire motion and the fingers will show the direction of the magnetic lines of force and the direction of the current, for a conductor in the ar- mature ofa generator. For the direction of current for a conductor in the armature in a motor, see left -hand rule. in cathode-ray tubes (CRTs). After 1963, transistor- based logic was added. Rich Text Format RTF. Also called Interchange For- mat. A document encoding file format developed by Microsoft that retains simple text formatting codes and basic text attributes (typestyle, size, bold, italic, underline, etc.). A widespread format that can be ex- ported and imported between word processing, OCR, and desktop publishing programs. It is a good inter- mediary fonnat to use when moving text with at- tributes from one system to another. Many people use ASCII to export/import text, and despair because the formatting is lost. You may wish to try RTF. Although there are different flavors of RTF, it usually works and can save hours of reformatting. Here is a very basic example of Rich Text Format showing the syn- tax for various formatting parameters. {\rtfO\ansi {\fonttbl\fO\fswiss Helvetica;} \paperw9880 \paperh3440 \margl12 0 \margr120 \p:mi\b<20\bGl20\fO\b\iO\uln::re\fs20\fCO\cfO Rich Text Format \bO RTF. Also called Interchange Format. A document encoding file format developed by Microsoft that retains simple text formatting codes, and basic text attributes (typestyle, size, \b bold \bO , \i italic \iO , \ul underline \ulnone , etc.). A widespread format that can be exported and imported between most word processing, OCR, and desktop publishing programs. It is a good intermediary format to use when moving text with attributes from one system to another. Many people use ASCII to export/import text, and despair because the formatting is lost. You may wish to try RTF. Although there are different flavors of RTF, it usually works, and can save hours of reformatting. Here is a very basic example of Rich Text Format, showing the syntax for various formatting rarameters.\ Rich Text Markup Language RTML. A proprietary programming language used by the Yahoo! Store to generate commerce-enabled Web sites. Yahoo! Store third-party developers provide selVices for automated Web site creation through their RTML tools. RTML is a combination HTML editor and commerce-spe- cific components development tool for adding the types of features that businesses like to include in their Web sites to support product promotion and sales. 817 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary wire electrically connected to the tip of the plug and another wire to the ring around the plug partway up the jack, nearer the insulated cord. The ring is tradi- tionally around -48 volts, with the negative charge used to help to prevent corrosion. See tip, tip and ring. ring errormonitor REM. In a Token-Ring network, "tokens" are passed around from machine to machine in a ring topology. A ring error monitor is a program that can be installed on machines in the ring to col- lect and signal ring-related errors in the form of soft errors and hard errors (MAC frames). Ring-related errors may include lost frames, tokens, or Frame Check Sequence (FCS) errors. ring-armature receiverA telephone receiver which began to be widely installed in the 1950s following the development and widespread use of the bipolar receiver. It differed substantially from earlierreceiv- ers in its details, incorporating a lighter, more effi- cient dome-shaped diaphragm, driven piston-like by magnetic fields across the armature ring. See bipolar receiver. ring-around-the-rosy A theoretical hazard situation on the phone system, in which acircular tandem con- nection exists, somewhat like an endless loop in a software routine. ring, network A type ofcircular network topology. See Token-Ring. Ring Again A telephone service that enables acaller to request notification if a busy number becomes available. When the number can be dialed, the caller's phone will ring and the call will be automatically placed on the caller's behalf, without the need to dial a second time, when the phone is picked up/activated. In general, only one Ring Again request can be set up at a time. See Make Busy. ring topology A network topology in which each sta- tion in the network is connected in a closed loop so that no termination is required. In this architecture, data packets are passed around the loop through each intervening node until they reach the destination ma- chine. Ring topologies are fragile in the sense that failure of one node or system affects the entire net- work. See/star topology, topology. ringback A usually undocumented, self-ringing tele- phone test number that can be used to verify a spe- cific phone number. In some regions, when a two- or three-digit number, followed by the expected phone number, is dialed, a new dial tone is provided, which can then be used for ringing tests. Ringback functions aid service technicians in verifying the functioning ofa newly installed or repaired system. They are also sometimes used for subscriber confmnation. In some regions, the ringback service connects the caller to a recording identifying the exchange in which the phone is located. See ringing tone. ringdown See ringing current. ringer, bell The mechanical or digital sound genera- tor that indicates the presence of an incoming call. The interval and type of tones generated vary from phone to phone, and even more so from country to country. With the proliferation of digital devices, it is likely that ringers will eventually be configurable. 818 You'll be able to load in a sound patch and have the phone sound like anything desired: a cat, a parrot, a jet airplane, your spouse's voice, etc. In fact, paired with a Caller ill system, there is no reason why the ringer couldn't switch to a device that says out loud, "Hank is calling, want to talk to him?" (This defini- tion was originally written in 1997. Since 2001, sev- eral wireless phone vendors have begun providing downloadable ringers to their mobile subscribers.) Ringer Equivalence Number REN. When telephone equipment is purchased and several devices are placed on the same line, there is a need for a way to designate and organize the ringer load on the line so as not to exceed the available current. In the United States, acertification number has been developed for telephone products which indicates that they meet certain specified requirements and guidelines. This REN helps installers and consumers set up various pieces ofequipment (phones, answering machines, fax machines) so that they will not interfere with one another when connected. Various devices on the same line may have different REN values. If a certain maximum number ofRENs is exceeded, the various devices cannot be guaran- teed to work correctly and may not ring. For example, a typical residential REN of5 requires about 3.6 V of ringing generator power, a power requirement that may be exceeded if the subscriber has a main phone, a fax machine, and four or more extension lines. Ringing generators for regenerating the local signal are commercially available to boost current to ring more devices than may be serviced by the public tele- phone system. For example, a high impedance 25-Hz output signal can power an additional 5 to 7 devices, depending on their ringing current needs. In some cases ring generators may be daisy-chained. F or central office ringing supply systems and emer- gency environments where ringing reliability is im- portant, redundant ringing generators may be used as a failsafe mechanism. All-digital systems often supply telephone services to environments with a variety ofdigital and analog equipment. In these instances, an ISDN t.erminal adapter may provide analog ringing capabilities to local devices through hook status circuitry and a com- pact on-site ringing generator. For data modems, the Ringer Equivalence Number is usually printed on the main chip in the center of the internal modem board, along with the Federal Communications Commission (FCC) registration number. It may also be listed on a label on the back of the device to assist the user in combining devices on a system. In most regions, the sum of the RENs on one line should not exceed 5.0. In Canada, the con- cept of Load Number is essentially the same as the REN. See ringing classification, ringing signal. ringing The production of an audible signal at the receiving end by means ofa mild AC or DC current to indicate signaling or the presence of an i1\coming call. In telephony, a ringing current is sent from the central office to the subscriber or from a local con- sole or branch to a local phone device. © 2003 by CRC Press LLC ringing cadence The rhythm (timing) associated with ringing signals on a telephone circuit. The ringing cadence varies depending upon the telephone com- pany and the country but typically is about 2 to 4 sec- onds of ring interspersed with 2 to 4 seconds of quiet. In historic systems, the ringing cadence was often supplied through rather picturesque rotating drum mechanisms, some of which were filled with mercury to close the circuit when the contacts reached the bot- tom of the drum. ringing classification A category established by the Federal Communications Commission (FCC) to de- scribe ringer types on telephone devices. Class A ring- ers respond to signals between 16 and 33 Hz; Class B ringers respond to signals between 17 and 68 Hz. Telephone devices are typically labeled as to ringer types. See Ringer Equivalence Number. ringing current, ringdown The current on a tele- phone system used to transmit ringing signals and ringing tones. This varies with the type of switching system and the distance over which it has to be car- ried. In traditional phone signaling systems, for ex- ample, the ringing signal is fed through the line as a 75 V current to generate a 20 Hz AC signal current for local calls, and 135 to 1000 Hz AC current for long distance. See talk battery. ringing generatorA low-power inverter system for generating ringing signals on telephone lines usually located at a central office or a local controlled envi- ronment vault. It is typically powered by a -48V cen- tral office or -24V DC private branch exchange power supply to generate a harmonic 20 Hz AC signal for local calls (higher current is used for long-distance calls). The generator produces a low-frequency alter- nating current (AC) that travels through the line to ring the alert bell in a subscriber telephone. It may also provide timing pulses. Multiple ringing genera- tors may be used for larger telephone exchanges or to provide a variety of ringing frequencies. Newer units may be selectable for a variety of frequencies typically ranging from about 17 to 50 Hz. There is no point in supplying ringing current to a line that is unavailable (off-hook), so a telephone sys- tem generally does not send a ringing signal until it has determined that the called line is available. If the callee's phone rings successfully, the ring is passed back to the caller so the caller can monitor the num- ber of rings. The ringing is stopped when the call is answered or the caller abandons the call. ringing key In a telephone switching system, a means by which the subscriber's telephone ringing is initi- ated by a key at the central office to indicate a call. Signaling current was sent as alternating current from a central office to the subscriber, a system that didn't work well for long-distance calls due to the loss of the signal over distance. ringing load The sum total, within a given time pe- riod, of subscriber telephones that may be ringing at anyone time. An estimate of ringing load is impor- tant when a centralized telephone system is being in- stalled, in order to determine the number and type of ringing generators needed to provide the ringing signals. See Ringer Equivalence Number, ringing generator. ringing signal Any signal transmitted over a tele- phone to initiate ringing on the receiving phone to indicate that a call is being placed. Various schemes for sending this signal have been used over the years to make it possible to send the ringing signal over distances without the current interfering with actual call transmissions. Typically a ringing signal is trans- mitted through an AC waveform at 20 Hz for local calls in North America (25 Hz in Europe), with higher voltages for long-distance calls. The ringing signal does not always activate the ringer on a telephone set. Modems use ringing signal de- tection circuits for autoanswer operations for com- puter bulletin board systems and phones for hearing impaired individuals or specialized environments may use the ringing current to activate a light rather than a bell. See ringing generator, ringing key. ringing tone, ringback A tone generated in the caller's line to indicate a call is being rout~d to a re- ceiving phone. The ring at the receiving end is initi- ated by a ringing signal sent from the central office or private branch switching system. This doesn't ab- solutely guarantee that the callee's phone is ringing. If the bell is defective or the routing of the call was in error (either through incorrect switching or because of dialing the wrong number), the callee may never hear the ring. See ringback, ringing signal. ringing voltage The amount of voltage applied in an analog telephone switching system to cause the called phone or other phone device to ring, usually about 88V. There is a limit to the number of devices which can be rung when attached to a single line, too many, and there will be interference with the ringing cir- cuitry. For more information, see Ringer Equivalence Number. RIP 1. See Routing Information Protocol. 2. See ras- ter image processor. 3. See Remote Imaging Proto- col. RISe See Reduced Instruction Set Computing. Ritchie, Dennis M. (1941-) An American Bell Labo- ratories researcher who codeveloped Unix in collabo- ration with Ken Thompson. He is well known for his development of the C programming language, along with Richard Kernighan. See C, Unix. Ritchie, Foster An inventor and early assistant of Elisha Gray who designed a writing telegraph in 1900 based on principles different from those originally patented by Gray a few years before. Known gener- ally as telautographs, these devices could transcribe handwriting across short distances and were in use for several decades. Riza, Nabell Agha (1962-) A Pakistan-born opti- cal engineer and inventor, Riza is responsible for sev- eral important developments in optical technologies. Riza studied at Cambridge University, the Illinois In- stitute of Technology, and CalTech. He subsequently worked at General Electric's Liquid Crystal Display Laboratory and, in 1995, joined CREOL as head of the Photonic Information Processing Systems Labo- ratory. In January 2001, he launched Nuonics, Inc.; 819 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary the same year, he was awarded the ICO Prize for discoveries and developments in the field of optics, many of which have become fundamental technolo- gies in optical engineering imaging and transmission technologies. See acousto-optic antenna control, multiplexed optical scanner technology. RJ The Universal Service Ordering Code (USOC) for Federal Communications Commission (FCC) - registeredjacks for connecting to a public network. USOC was developed in the 1970s by AT&T and the communications industry is widely standardized on this system. Each type ofjack has a number of wir- ing configurations, depending upon the number of wires connected. Thus RJ -25 wiring uses the same jack as RJ-Il except that eight wires are connected instead of two. Wires are often connected in pairs. To promote pair continuity in electrical receptacles with varying numbers of active wires, the wires are usually connected in pairs working out from the center. In the Sample of Common Wiring Jacks chart, C rep- resents flush or surfaced mounted, W represents wall mounted, and X is complex line. RJE See remote job entry. RJEP See Remote Job Entry Protocol. RL 1. radio locator. See radio beacon. 2. resistor logic. 3. return loss. RLCM Remote Line Concentrating Module. RLE See run length encoding. RLP See Radio Link Protocol. 2. See Resource Lo- cation Protocol. RM See Resource Management. RMA, RA returned merchandise authorization. A coding system used to contro I and track returned merchandise. See return authorization. RMF remote management facility. rms See root mean square. RMF read, modify, write. rnA full-screen, configurable news reader developed by Larry Wall, the author of the Perl programming language, and released in 1984. Wayne Davison de- veloped a superset of rn known as tm. RNC radio network controller. RNG See random number generator. RNX Restricted Numeric Exchange. A local tele- phone exchange in which calls are restricted to the originating network. Suppose a number is 555-1111 when dialed from outside the local exchange. The first three digits are the NXX digits. From inside the re- stricted exchange, you might instead dial 105-1111, with 105 being the RNX digits. The call then rings through to the number without passing through cir- cuits outside the local exchange. See NXX. RO 1. receive only. 2. remote operation. 3. recovery operation. ROA recognized operating agency. An agency tasked with operating a private or public telecommunications service such as the public land mobile network. roaming Using wireless telecommunications ser- vices while moving around, either on foot or in a vehicle. The logistics of designing and managing Sample of Common Wiring Jacks Described in Universal Service Ordering Code (USOC) Jack Wiring Notes RJ-ll Can accommodate up to six wires, though typically only two or four are connected as one or two pairs. A very common type of single-line phone jack used for telephones, modems, and fax machines. RJ-IICIW One pair of wires connected, as for a single line phone. Traditionally the green and red wires are connected as tip and ring for the fust line. The connection is bridged. RJ-14CIW Two pairs of wires connected, as for a two-line connection, e.g., line 1 might be a phone or answering machine and line 2 a modem or fax machine. Traditionally green and red are assigned as tip and ring for the frrst line, and black and yellow as tip and ring for the second line. The connections are bridged. RJ-25CIW All three pairs configured. Thus, line 1 might be a phone, line 2 a modem, and line 3 a fax machine. RJ-45 Can accommodate up to eight wires and is common for multiple line phones (up to four lines) and for data communications, especially Ethernet and Token-Ring. RJ-48C/x Four wires are typically connected as two pairs to provide 1.54 Mbps digital data network services. RJ48S Four wires are typically connected as two pairs to provide local digital data network services. RJ61X Four pairs of wires connected to accommodate four phone devices. Three lines are bridged. IOBase-T Twisted Pair. Pairs two and three are connected. 820 © 2003 by CRC Press LLC roaming subscribers is quite complex and requires sophisticated software. See cellular phone. See Inter-Access Point Protocol. robbed bitA bit commandeered in atransmission for something other than its usual purpose. This tech- nique may be used to acquire extra bits for signaling information, especially if the signals are only occa- sionally needed. See robbed-bit signaling. robbed-bit signaling RBS. In data communications, a means of taking one bit from a data path to provide signaling information. For example, in voice commu- nications over in-band Tl systems, a bit may be robbed to indicate the hook condition of the line. Roberts, H. Edward Founder ofMITS, which de- veloped and distributed the first commercially suc- cessful computer kit, the Altair 8800, that launched the microcomputer industry. Roberts codesigned the computer when the market for calculators began to slip. Roberts left MITS in 1977 and is now a physi- cian. See Altair. robot In its simplest form, a robot is a mechanical apparatus which automatically moves or senses ac- cording to a set program, or an adaptive program. In its most complex form, it is a sophisticated electro- mechanical logical device that can interact with its environment in ways which are ascribed to human intelligence. That is, it is adaptive, and responds in ways appropriate to its task or to its benefit. Robot arms are used in many production-line tasks, whereas many humanlike robots are portrayed in science fic- tion stories and films. A humanlike robot (in form and functioning) is called an android. A robot is generally associated with hardware and physical forms, but with the development of software artificial intelligence techniques, online avatars that seem to have ahumanlike presence on public forums and chat lines have also been called robots, or more commonly 'bots or bots. Abot can be online 24 hours a day, can monitor processes, log user activities and interaction, and more. Bots have been banned from some of the chat rooms due to badly programmed bots violating chat Netiquette. However, system operators sometimes have authorized bots running on Internet Relay Chat (IRC) to perform many useful functions. Bots are also associated with search engines. Just as IRC bots do housekeeping tasks on the chat channels, search bots do useful Web page search and retrieve jobs, like a crew of gofers ("go fer this, go fer that") working around the clock. See mailer daemon. Robotic Telescope Markup Language RTML. The Berkeley Lab had acquired a 3D-in. telescope for as- tronomical research on supernovas that was installed at the Leuschner Observatory. To automate the func- tions of the telescope, the scientists created a tele- scope control system to support scheduling, data-ac- quisition, database management, and image analysis, thus treating the telescope as a remotely controlled robotic device. Since other telescopes were being controlled by various, similar in-house systems, it seemed appropriate to come up with a simple, stan- dardized, high-level language that could provide a user with access to a broad range of devices - the concept for the Robotic Telescope Markup Language. Initial discussions with telescope manufacturers indicated an interest in supporting RTML commands that users could access through the Web and the Hands-On Universe Project endorsed the concept and provided an initial plan for development. Thus, the first version was released as the Remote Telescope Markup Language. See Remote Telescope Markup Language. ROC 1. rate of convergence. 2. record of comments. 3. Regional Operating Company. See Regional Bell Operating Company. rocket camera A creative early 1900s invention for taking photographs at high altitude (close to 800 m) by attaching a camera to a stabilizing rod and equip- ping it with a small parachute. Rocky Mountain Bell Telephone Company An early Bell telephone exchange, established in 1883, with financial assistance from American Bell Com- pany. It rapidly acquired the Ogden Telephone Ex- change Company, the Montana Telephone & Teleg- raphy Company, the Idaho Telephone & Telegraph Company, and the Park City exchange. This pattern ofacquisitions continued for a number of years. Rocky Mountain Telephone Company An early telephone exchange established in Salt Lake City in 1800. ROD rewritable optical disc. roentgen, rontgen (symb. - R) An international unit ofX-radiation or gamma radiation which is equal to the amount ofradiation which produces one electro- static unit (esu) of charge in one cubic centimeter of dry air at DoC and standard atmospheric pressure ion- ization ofeither sign. Rogers receiver An early batteryless radio receiver first introduced in 1925 at the Canadian National Exhibition in Toronto. ROH receiver (as on atelephone) offhook. ROLC Routing Over Large Clouds. The ROLC Working Group has now merged with the IPoverATM Working Group to fonn Intemetworking over NBMA (ION). See frame relay, Intemetworking over NBMA, RFC 1735. role-playing game RPG. This style of game is par- ticularly popular on computer networks as it can be implemented with simple text interfaces and lends itself to including people who are anonymous in the sense that the players, located at different terminals, cannot see one another. In general, game-playing is discouraged on computer terminals in schools and businesses unless it directly relates to course work, but role-playing games have been tolerated since many of them require players and playmasters to use certain programming commands and algorithms to set up the game and participate, thus justifying their educational value. Role-playing games can be addictive, however. More than one role player has failed a school term due to overindulgence. Roll AboutAcommercial, self-contained videocon- ferencing unit which includes the monitor, camera, microphone, and other components on a stand that can be moved from one office to another as needed. 821 © 2003 by CRC Press LLC . receiverA telephone receiver which began to be widely installed in the 1950s following the development and widespread use of the bipolar receiver. It differed substantially from earlierreceiv- ers in its details, incorporating a lighter, more effi- cient dome-shaped diaphragm, driven piston-like by magnetic fields across the armature ring. See bipolar receiver. ring-around-the-rosy. ofa manual phone jack in an old telephone switchboard in which the large plug was divided into two sections, with an internal - -5 Right-Hand Rule for Current Direction N RIF See rate increase factor. RIFF 1. raster image file format. See raster. 2. Re- source Interchange File Format. A platform-indepen- dent multimedia specification developed in the early 1990s by a group of. by CRC Press LLC Fiber Optics Illustrated Dictionary new revisions occur. RF 1. See radio frequency. 2. range finder. A device for determining distance (and sometimes also direc- tion). See radar. 3. raster file. See raster. 4. rating fac- tor. RFA 1. See remote file access. 2. request for action. RFC 1. See Request for Comments. 2. required for compliance. RFD See Request for Discussion. RFF