Fiber Optics Illustrated Dictionary toward the radiant energy source. The four beams of light exiting from the pyramid are re-imaged with a display system to yield four images. The pyramid acts like a knife-edge test system, revealing optical aber- rations carried by the light electromagnetic beam. The system has been tested in astronomical applications. See knife-edge focusing. pyrheliometer An instrument for measuring infrared radiation which borders the visible spectrum on one side and radio waves on the other. pyroelectric detectorA detector that takes advantage of the characteristic ofapyroelectric material to build up a charge when exposed to pulsed or modulation radiant energy. Due to the quick response times of pyroelectric detectors, they are more useful for some types of applications and environments than other types of thermal detectors that have difficulty sepa- rating the impulse heat from ambient heat due to slower response times. See photo detector, pyroelec- tric, thermocouple. pyroelectric A usually crystalline substance having polarized molecular properties in the absence of ap- plied voltage. When stimulated by heat, the molecules become more active, expanding and altering the po- larization of the material enough to build up an elec- trical charge on opposite surfaces of the material. Thus, a subtle electromagnetic impulse flows between the surfaces. pyroelectricity Electromagnetic charges created through a change in temperature. Pyroelectricity re- fers to the means of generating the charge, not the nature of the charge itself, which is the same as oth- ers. Crystals have valuable osci llating characteristics and are commonly used in timing mechanisms and radio electronics and some have interesting pyroelec- tric activity when exposed to heat. See pyroelectric, pyroelectric detector. pyromagnetic effect The combined effect of heat and magnetism in a material or circuit. pyrometer An instrument for determining tempera- ture, that is, a heat sensor for detecting and option- ally quantifying thermal radiation. A pyrometer is generally used in situations hotter than those mea- sured by a traditional mercury thermometer, espe- cially where non-contact temperature is assessed. Temperature can be measured in a number of ways by electrical resistance, optical, or other radiant en- ergy emissions. Thermal radiation may be assessed by measuring the brightness (intensity) ofradiant en- ergy within a narrow portion of the thermal spectrum. Another means is by evaluating data collected in two different wavelengths (usually red and green) to in- fer temperatures in the higher ranges (picture the way an electric stove element changes color as it heats). Infrared heat detectors (spectral radiation pyrometers) 772 have traditionally been combined with optical lenses and reflectors to make pyrometers. Initially, fiber optic cables were not seen as good infrared lightguides, but improvements in fiber optic technolo- gies and control ofspectral characteristics have made it practical to develop new fiber-based pyrometers. A fiber-based probe can be quite tiny and enables placement of the rest of the electronics at some dis- tance from the probe, which is very useful for medi- cal and industrial applications, especially those that involve insertion into constrained spaces or where there is high electrical activity that could interfere with electronic probes. The temperature range to be sensed with a fiber-based probe and the length of the fiber are related, with lower temperatures having lower limits on the length of the fiber cable. The angle ofacceptance of the fi- ber endfaces (or a lens associated with the fiber endfaces) determines the breadth of the sensing area and how closely the device must be held to the heat source for accurate readings. By combining fibers with lens focusing geometries, it is possible to design heat probes with very precise tolerances suitable for medical evaluation or industrial applications such as quality assurance and microfabrication. Unfocused fibers are suitable for general purpose applications where specificity of individual temperature regions is not critical. Where practical, backlighting the tar- get object can provide a visual guide for aligning the probe. Pythagorean Theorem The SUIll of the squares of the sides (A, B) ofa right angle triangleequals the square of the hypotenuse (C). Pythagoras' theorem, Pythagorean theorem A mathematical rule that states that, in a right-angled triangle, the sum of the squares of the sides is equal to the square of the hypotenuse (the longest side). This theorem is widely used in mathematics for calculat- ing distances and other measures. It is named for the Pythagoreans, a philosophical group connected with Pythagoras. © 2003 by CRC Press LLC q 1. symb. quantum value. 2. symb. electrical quan- tity in coulombs. See coulomb. Q 1. abbrev. quality. See Q factor. 2. abbrev. queue. See queue. 3. A merit indicator for acapacitor or in- ductor equal to the reactance divided by the resis- tance. 4. In a resonant circuit, an indicator of the sharpness or resolution of the resonance. It is calcu- lated by taking the resonant frequency and dividing it by the resonant bandwidth. See Q-switch. Q address A storage location for data, from which the information can be accessed and retrieved. QantennaA type of dipole antenna in which the feed line impedance is made to match the radiometer cen- ter impedance by the interposition of avertical sec- tion, consisting of parallel bars between the two. Qbit In an X.25 network, the Q bit is a binary indi- cator located at the beginning ofa data packet, im- mediately preceding the D bit. The Q bit signals the existence of user data or qualified data in the form of control information. Protocols in higher layers can set this bit to one (1) to indicate control packets, oth- erwise a value of zero (0) indicates data packets. See D bit, M bit. Q channell. In NTSC color television broadcast- ing, a frequency band in which green-magenta color information is transmitted. 2. In ISDN Basic Rate Interface (BRI) SIT interface implementations, an 800-bps maintenance channel. 3. In data transmis- sions, a channel associated with an I channel in modu- lated transmissions (e.g., phase-shift keying). See Q signal. Q demodulation Demodulation of an incoming broadcast signal in a color television receiver to com- bine the chrominance signal and the color-burst os- cillator signal in order to recover the Q signal. Qfactor (symb. - Q) quality factor. 1. In electronic circuits, a means of describing the desired character- istics ofa system. The terms of the Q factor vary de- pending upon what is described (capacitance, induc- tance, etc.). In a digital circuit, for example, the Q factor may be used to characterize the signal-to-noise ratios of the two digital states. The concept has tra- ditionally been associated with electrical voltages and wired communications, but can be generalized to optical communications. Generally, a higher number is used to indicate a more efficiently operating com- ponent. In lasers, for example, a maximal Q-factor may be associated with a filled laser resonance cav- ity, where the signal-to-noise ratio is high and switch- ing may be triggered. The Q factor may be used as a figure of merit (e.g., for assessing bit error rates). See bit error rate. 2. See Q-factor. Q multiplierAcircuit used to enhance the selectiv- ity ofa component by feeding the signal back through the resonant network. This was used in early super- heterodyne receivers, but various types of filters have, for the most part, superseded it. Qoutput The reference output of an electronic flip- flop state, which may be one or zero. QSeries Recommendations A set ofITU-T recom- mended guidelines for switching and signaling. These are available for purchase from the ITU-T. Some of the related general categories and specific Q category recommendations are included in charts on the fol- lowing pages to give a sense of the breadth and scope of the topics listed here. A full list of general catego- ries is listed in Appendix C and specific series topics are listed under individual entries in this dictionary. See also I, V, and X Series Recommendations. Qsignal 1. In various data transmission schemes, it is common to split a signal and to alter the character- istics of one or both of the two data streams so that they can be transmitted together without excessive interference or crosstalk. A Q signal or quadrature- phase signal is one of two common streams; the other is the in-phase signal or I signal, into which data are commonly split in various modulation systems. See quadrature amplitude modulation. See I signal. 2. A telegraph code shorthand signal consisting of two let- ters prefaced by a"Q" that is still well known to ama- teur radio operators. For example, QST is a general call preceding a message addressed to all members and amateurs. As such, it is also the name of the jour- nal of the American Relay Radio League (ARRL). SeeQBF. Q spoiling A technique used with lasers in which a more powerful burst or pulse is attained by inhibit- ing the action of the laser for a few moments, to al- Iowan increase in the number of ions, and then Q switching to allow the extra burst of light to be emitted. 773 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary ITU-l'QSerlesReeommendations Q.721 .Signaling System No. 7 functional description of the Signaling System No. 7 Telephone User Part (TUP) In band and out~band Q.20 Comparativeaqvantages. of 44in-band" and "out-band" systems Q.21 Systems recommended . for out-band signaling Q.22 Frequencies to be· used form-band si~~Jin9: Q.25 Splitting arrangements and signal recogniti9Ptin1~s in"in~b~net"·signaling systems :Splittingarrangemellts and signal recognitiQQ times in "in-band" signaling systems: BhQne·featuresandsi nals Q.23 Tecl1nicalfeaturesofpusll-buUOD telephone:sets Q.24 Multifrequencypush-button·· signal reception Q.27 Transmission of the answer signal Q.~8 Petennirmtionoftbemoment ofthe called subscriber's answer in the . automatic service Q.35 Technical characteristics of tones for the telel'honeservice Q~1()9!raI1SDlis~ion<?ftheanswer signal in . .international·exchanges Networkaceess Q.33 Q.44 Q.26< ··Directacpesstothe~temational networkfrom#le national network Quality of transmissions; interference and noise Q.32 Q.29 :·@ausesornoise.andwaysofreducing noise in telephone exchanges 0.30 Improving the reliability of contacts in spe~cp cir.cuits Q.31 . Noiseinanational4-WireautoIllatic excljang~ Reduction of the risk of instability by s'Vitchingm~Mls Protc:ctiopaga.ipst effeetsQf faulty tratl.slllissiolt·Ofl.grOUpS·· ofcircuits Attenuati(}n etistortion Q.4 Automatic s:witchillg futlctions for lise in. national···netWorks Q.5. J\dvan~~es(lfs~jaut()matieservice ·~tl the intemationalteleph()ne service Q.6 ~ A.dvant~ge.s~fjll~J;natj@11aI. t!1.1 to matic working Signaling systems Q.7 Signalmg systemstcrbe'usedfor imemiti9~~J .• · .•. ~~ff'Wtltif;· .•• ~:p.<i semiautomatic·telephoite.working Q.8 . Slgtlalit1gsY§telll~~t(l"euseqfor mtemationalmantialand automatic workirIgontplalogtle leasedcircqits Q.48 Dematldassi~Dlc;ntsigpalin~ systems Q.SO Signaling between circuitmultiplication ~quip~ent. (GMJ;l' and .~t~m~ol1~l sWitching· centers(ISC) Q.55 Signalipg bet,weeqsignalproc:essing networkequipmerit and international ~witchijlg c.m~~ Q.698 Inte1Workin~of signa1iJlgsystemNo. 7 ISUP,TUP,and signa1mg system No. 6 using arrowcliagrams Q.700 ·Introdtictiol'f<td·C€ITTSignalirig··System No.7 Q.701 ·FlUlctionaldescriptionhf the' message trllll~ferpart (MTr) o(~~gnaling§ysterJ1 No.7 Voc~bu1a1"y of s\Vitc\Ung and signaling terms . Tel~IJlJ11uni~~~on~pplications .~or 'switches ~d ~Jl1PUters (TA.SC)~ gen~J:81~~~rvi~~ Q.1302 Tel~IJPtlunic1\ti(')napplicationsfor·· :switches·· ~dc2tnPHt~ (f?\SC) TASe funCtionalservices Q .1303 Teleqo111II1lJ11ip,~ion.~pp1icatiot)~for switches and computers (TASC) - TASG~~g~~l.lt:archjtectur~, . methodology . and requirements Q.1290 :Glossat"}'Qftertpsus~ .i!l~he definition of intelligent networks Q.120 llI~312~ncipJesofintenigetltnetwork architecture Q.12021I.328lliteIIigentNet\Vork·· >service ~lanellrchi~~~~ Q.12031I.329 IntelligentNetwork-global f)JncHQPaJpla.n~~cJJi~tlJr~ Automatic. and semiautomatic switchin 774 © 2003 by CRC Press LLC ISDN and·B-ISDN Q.71 ISDN circuit mode.switchedbearer services Q.80 • Introduction to Stage 2 service descriptions for supplementary services Q.81 Number identificatio11 Q.82 Call offering Q.83 Call completion Q.84 Multiparty Q.85 COl1lttluttlty. ofinterest Q.86 Charging Q.87 Additional infotmation transfer Q.761 Functional description of the ISDN user- part of Signaling System No.7 Q.762 General function of messages and signals of the ISDN user part of . Signaling System No. 7 Q.763 .Fonnatsand codes of the ISDN. user part of Signaling System No.7 Q.764 Signaling System No.7 ISDN user part signaling procedures Q.767 Application of the ISDN user part of CCITT Signaling System No. 7 for international ISDN interconnections Q.768 Signaling interface between an international switching centre (ISC) and an ISDN satellite subnetwork Q.850 Usage of cause and location in the digital subscriber signaling system no 1 and the Signaling System No. 7 ISDN user.part Q.860 ISDN and B-ISDN Generic Addressing and Transport (GAn Protocol Q.920 DSS 1- ISDN user-network interface data link layer, generalaspects Q.92 I ISDN user-network interface, datalink layer specification Q.922 ISDN data link layer specification for frame mode bearer services Q.923 Specification ofa synchronization and coordination function. for the provision of the OSI connection-mode network service in an ISDN environment Q.930 DSS I-ISDN user-network interface layer 3, general aspects Q.931 DSS 1- ISDN user-network interface layer 3 specification for basic call control Q.932 DSSI-genericprocedures for the control of ISDN supplementary services Q.933 ISDN DSSI - signaling specification for frame mode basic call control Q.939 TypicalOSS1 service. indicator codings for ISDN telecommunications services Q.940ISDN user-netWork interface protocol for management, general aspects Q.950 ISDN suppletnentaryservices protocols, structure, and general principles Q.9SI·· .• ·Numberidentificatiol1 Q.9S2 Stage 3 description forcall offering supplementary services.using DSS 1- diversion supplementary services Q.953 . Cal L completiQJ1 Q.954 •Multiparty Q. 95 5 Community of interest Q.956 Charging Q.967.· .•. Additional .• informationtransfer Q.l901 Bearer-Inde}lendentCaIlControl Protocol Q.1950 Bearer-Independent CallControl Protocol Q.1970 Bearer-IndependentCallContr()lIP Bearer Control· Protocol Q.1990 Bearer-Independent CallControl Tunneling frotocol Q.20 10 Broadband mtegrateclserVices digital network overview- .signaling Capability Set 1 (CS-l) Q.2100 B-ISDN signaling ATMadaptation layer (S~) ovetviewdescription Q.2110 B-ISDN ATM.adaptationJayer- service specified connection oriented protocol (SSCOP) Q.2111 Service~SpecificCol1nection Orientetf Protocol in a multilink and connectionless environment (SSCOPMCE) Q.2119 B-ISDNA.TMadaptati()111ayer-:- convergence function forSSCOP above the.frame relay core service Q.2120 B-ISDNmeta-signalingprotocol Q.2130 B~ISDN siitJ.aling ~TMadaptation layer - service-speciticcoordinatiort function for support of signaling at the user network interface (SSFC AtUNI) Q.2140 B-ISDN ATM adaptation layer- servicespecifjc coordination function for signaling at the network node interface (SSCF at NNI) Q.2144 B-ISDN SignalingATMadaptation l~yer(SAAB)-larerln~agementfor the SAALatthe netvvork:node interface (NNI) Q.2150 AAL2 signaling transport converter Q.2210 Messagetnmsfer part l~vel 3 functions and messages Itsing the services ofITU-T Recommendation Q.2140 775 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary ITU-T QSeries Recommendations,cont. ISDN and B-ISDN. cont. Q.2610 B-ISDNusage of cause andlocation in B-ISDN user part and DSS-2 Q.2650 B-ISDN- intemetwQrking between Signaling System No.7 B-ISDNUser Part (B~ISUP)and digital subscriber Signaling System No.2 (OSS-2) Q.2660 B-ISDN- intemetworking between signaling SystemNo. 7 B-ISDNUser Part (B-ISUP) and N-ISDN User Part (N-ISUP) Q.2723 Extensions to SS7 B-ISDN User Part (B-1 SUP) Q.2725 B-ISDNUser Part CS-2.l See Q.2761 throughQ.2764 Q.2726 B-ISDN User Part eS-2.I See Q.2761 through Q.2764 Q.2727 B-ISDNUserPart (B-1 SUP) support of Frame Relay Q.2730 B-ISDN- S87B-ISDN User Part (B- ISUP) supplementary services Q.2735 Stage 3description ()fCommunity of Interesfsupplementary services for B- ISON using SS7 Q.276 1 B-ISDN - functional description of the B-ISDNUser Part. {B-ISUP)ofSS7 Q.2762 B-ISDN-generalfunctions of messages and signals of the B-1 SUP of S87 Q.2763 B-ISDN - SS7 B-ISDN User Part (B- ISUP)-Formats and codes Q.2764 B-ISDN- 8S7 B-ISDN User Part (B- ISUP) -Basic call procedures Q.2765 B-ISDN S87 B-ISUP-Application Transport Mechanism (APM) Q.2931 B-ISDN-Digital Subscriber Signaling System No. 2(OS8 2) - UserNetwork Interface (UNI)Layer 3 specification for basic call/connection control Q.2934 B-ISDN DSS-2switched virtualpath capability Q.2941 B-ISDNDSS 2extensions Q.295 1 B-ISDN - Stage 3 description for number identificati9n supplementary servicesusingB-I8DN D88-2- basic call Q.2955 B-ISDN DSS-2 - stage 3 description for community of interest supplementary services-basic call Q.2957 B-ISD~DSS-2 - stage 3 description for additionalinfotnlation transfer supplementary services - basic call Q.2959 B-ISDNDSS-2-(;all priority Q.2961 B-ISDNDSS-2 -support of additional parameters 776 Q.2962 B-ISDN DSS-2 - connection characteristics negotiation during caUl connection establishmentphase Q.2963 B-ISDN DSS-2 - extensions for ATM Q.2964 B-ISDNDSS-2 - basic look-ahead and other clauses Q.296S B-ISDN DSS-2 - Quality of Service (QoS) issues Q.2971 B-ISDN - digital subscn"ber DSS-2- user network interface Layer 3 specification for point-to-multipoint calVconnection control Q.2981 B-ISDN and B-PISN - call control protocol Q.2982 B-ISDN DSS-2 - Q.293 I-based separated call control protocol Q.2983 B-ISDN DSS-2 - Q.2931-based bearer control protocol Q.2984 B-ISDN and B-PISN - prenegotiation for multiconnection Q.2991 Abstract test suite for the network integration testing for B-ISDN and B-ISDNIN-ISDN Modeling, Intelligent Networks Q.76 UPT functional modeling and information flow Q.1200 Intelligent Networks (INs) recommendation structure Q.1201 Principles of Intelligent Networks architecture Q.1202 Intelligent Networks - service plane architecture Q.1203 Intelligent Networks - global functional plane architecture Q.1204 Intelligent Networks - distributed functional plan architecture Q.120S Intelligent Networks - physical plane architecture Q.1208 General aspects of the Intelligent Networks application protocol Q.1210 Q l2xxseriesstructure for Intelligent Networks Q.1211 Introduction. tg IntelligentNetworks Capability Set 1 (CS-l) Q.1213 Global functional plane for Intelligent Networks· CS-1 Q.1214 Distributed functional plane for Intelligent Networks CS-] Q.1215 Physical plane for Intelligent Networks CS-l Q.1218 Interface recommendation· for Intelligent Networks CS 1 Q.1219 Intelligent Networks user guide for CS-l Q.l220 Q.l22x seriesIntelligent Networks Capability Set 2 (C8-2) recommendation structure Q.1221 Instruction tolntelligent Networks CS-2 © 2003 by CRC Press LLC Q.1701 Framework for 1MT-2000networks Q. t 711 Functional model for 1MT 2000 networks Q.1721 Information flows for IMt~2000CS-l Q.1731 Radio technology independent :requirementsfor 1MT-2000 Layer 2 radio interface .··.\i :/:) .>: Q.17S1 Internetwork signaling requirementsfor 1MT-2000CS"1 Wireless. communications Q.1222 Service plane for Intelligent Networks CS-2 Q.1223 G10tial functional plane for Intelligent Networks CS-2 Q.1224 Distributed functional plane for Intelligent Networks CS-2 Q.1225 Physicalplane forJ l1 telligent Networks CS-2 Q.1228 Interface recommendation for Intelligent Networks CS-2 Q.l229 IntelligentNetworksuser's guide for CS-2 Q.1231 Introduction to Intelligent Networks Capability Set 3 (CS-3) Q.1236 Intelligent Networks CS-3 Management Information ModeJ requirements and methodology Q.1237 Extensions to Intelligent Network CS-3 in supportofB-ISDN Q.1238 Interface recommendation for Intelligerit NetWorkCS-3 Q.1241 Introduction to Intelligent Networks Capability Set 4 (CS-4) Q.1244 Distributed functional plane for IntelligentNetworks eS-4 Q.1248 Interface recommendation foI' Intelligent NetworkCS-3 Q.1290 Glossary oftenns for Intelligent Networks (included in Q.9) Q.1300 Telecom applications for switches and computers (TASC) general overview Q.1301 TASe - architecture Q.1302 TASe - functional services Q.1303 TA8C management, architecture, methodology, and requirements Q.1400 Architecture framework for the development of signaling and organization, administration, and maintenance protocols tlsing·OSI concepts Q.1521 Requirements on· underlying networks and signaling protocols to support UPT Q.1531 UP! security requirements for Service Set 1(8S-1) Q.1541 UP! Stage 2 for 8S-1 on SC-t-1995: procedures for UPT functional modeling and infonnation flows Q.1542 UPT Stage 2 forSS-l on CS-2- procedures for universal personal telecommunication functional modeling and information flows Q.1551 Applieation·of IntelligentNetwork application protocols (INAP) CS-l for UP! SS-1 Q.1600 Signaling System No.7 interaction between ISIUP atIdINAP Q.1601 Signaling System No. 7 interaction between N-ISDN and INAP CS-2 Q.14 Q.lOOO Q.1001 Q.I002 Q.1003 Q.l004 Q.lOOS Q.1032 Q.lOSl Q.I100 Q.l 101 Q.ll11 Q.1112 Q.l1S1 152 Q.l231 Means to control tbenumbel"of satellite links in an international telephone connection Structure of the QJOOOseries fecommenda~ons forpubJicJand mobile networks General aspects of public land mobile networks Network functions(or public land mobile networks Locationregistratioh prdcedures for public land mobile networks Location register restoration procedures forpublic'landmobile. networks Han dover procedures for public land mobile networks Signaling requirements relating to routing ofcaUsto mobile subscribers Mobile application partfor publiclart(f mobile networks Interworking with StandardA ThfMARS~l'. systell1- structure of the Recommendations on theINMARSA1 mobile sat~llite systems General requirements for the interworking of the terrestrial telephone network and INMARSATStandardA system Interfaces between the INMARSAT. standard B system and the international public switched telephone networkl ISDN ProceduresforihtetWorkmgbetween INMARSAT standard-B.system and the international public switched telephone networklISDN Interfaces ·for iIlterworkil1g between the INMARSATaeronautical mobile- satellite system and the international public switched telephone network! ISDN Proceduresforintenvorking between INMARSAT aeronautical mobile satellite system and the international public switched telephone network! ISDN Extensions to ··ttltetligent.NetworkCS-3 in support ofB-ISDN 777 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary Q-band A microwave frequency spectrum ranging from 36 to 46 GHz, between the Ka-band and the V -band. Frequencies in this range tend to be used for radar and small aperture satellite transmissions. See band allocations for a chart of designated frequencies. Q-factorA measure of frequency selectivity, or the "sharpness" of resonance in a resonant vibratory sys- tem which has one degree of mechanical or electri- cal freedom. See Q factor, Q-switch. Q-switch In laser resonating cavities, a mechanism for opening and closing the cavity to allow or block the laser light to produce laser pulses rather than a continuous wave. This mechanism can be constructed with acousto-optic or electro-optic devices (e.g., Pockels cells). The term comes from the high signal- to-noise ratio (Q factor) that is characteristic of an amplified signal in a filled laser resonating cavity. In acousto-optical switching, incident light from the laser is deflected when it comes in contact with acous- tical waves (e.g., in a modulating crystal) and is scat- tered so that there isn't sufficient focused energy to exit the resonating cavity. In electro-optical switching, incident light from the laser hits a polarizing "shutter" such that the light will pass or not pass. Thus, Pockels cells, in conjunction with a polarizer, act as a Q-switch to alternately al- low the laser cavity to be filled or emptied in a pro- cess sometimes called cavity dumping. Pockels cells may also be configured/assembled with other com- ponents to allow a portion of the pulse to exit before the cavity is fully filled (amplified). See pockels ef- fect, Q, Q-factor. Q- Telecom A business unit of Info-Quest providing telecommunications services to Greece as one of four GSM suppliers in the country. In June 2002, it was announced that Q- Telecom would deploy Harris Cor- poration point-to-multipoint digital radio systems throughout Greece. Q.SIGA global common channel signaling protocol (CCS), based upon the ISDN signaling protocol, used in the digital transmission of voice over digital net- works such as ATM. In addition to the features in the ISDN signaling protocol, Q.SIG includes private branch exchange (PBX) features so a network of PBXs can interact as a distributed system. CCS sys- tems are more prevalent in Europe than in the United States. See voice over ATM. QA 1. quality assurance. 2. queued arbitrated. In DQDB, an information field segment used to trans- fer slots when they arrive through a nonisochronous transfer. QAM See quadrature amplitude modulation. QBE See query by example. QBF, fox message QBF = "quick brown fox." The Q signal code to send a test sentence that includes all the letters of the English alphabet. A QBF message is commonly used to verify whether all letters avail- able to a device or contained within a coding system are present and/or working correctly. It is familiar to most as "THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG" (which is then repeated in lowercase, if needed). The idea is to convey the 778 entire alphabet in the shortest sentence that is com- fortably memorable as possible. In wireline devices, it is more often called a "fox message" since Q sig- nals are associated more specifically with radio fre- quency communications. The phrase "fox message" is used more generically to test alphabetic commu- nication signals and the physical integrity of type- writer or computer keyboard keys. See Q signal, Z code. QC quality control. QC laser See quantum cascade laser. QCELP See Qualcomm Code Excited Linear Pre- dictive Coding. QCIF See Quarter Common Intermediate Format. QCT Qualcomm CDMA Technologies. See Qual- comm Code Excited Linear Predictive Coding QD See queuing delay. QD-DOS, QDOS A historic microcomputer operat- ing system (Quick and Dirty Operating System) de- veloped by Tim Paterson, which was derived from a mid-1970s manual describing Gary Kildall's CP/M, and extremely similar in syntax and functionality. At that time, ffiM was looking for an operating system for its line of microcomputers. ffiM contacted Mi- crosoft about contracting their (computer language) products, thinking they had also purchased the rights to CP/M. When they found that Microsoft didn't have an operating system, they went to visit Digital Re- search (originally Inter-Galactic Research), but the DR representative was reluctant to sign ffiM's non- disclosure agreement on DR's behalf, especially when the attorney didn't like the terms of the contract. ffiM went back to Microsoft and DR thought it would have a further opportunity to talk terms with ffiM, especially since Microsoft didn't have an operating system that could meet ffiM's needs at the time, as they had been concentrating their efforts on devel- oping computer languages. Microsoft, however, promised one to ffiM in a very short time period, and delivered on the contract by purchasing the code for QDOS from Seattle Computing, the company for which Paterson was working. They provided it to ffiM who released it as PC-DOS. Microsoft subse- quently purchased the distribution rights for QDOS for $50,000 and later released a slightly altered ver- sion of PC-DOS as MS-DOS (Microsoft Disk Oper- ating System). Microsoft managed to stipulate con- tractually that they could retain the rights to sell the product they had developed for ffiM, in competition with ffiM. Thus, QDOS, derived from CP/M became IBM's product, rather than CP/M itself: and evolved into MS-DOS, and eventually Windows. See CP/M, Microsoft Corporation, MS-DOS, Digital Research. QDU See quantizing distortion units. QFA See Quick File Access. QFC See Quantum Flow Control. QFM See quadrature frequency modulation. QIC quarter inch cartridge. See Quarter Inch Car- tridge Drive Standards. QICC 1. See Quad Integrated Communications Con- troller. 2. See Quad International Communications Corporation. © 2003 by CRC Press LLC QIP A commercial Internet Protocol (IP) address management software product from Quadritek (now Lucent IPGSP) that facilitates the central manage- ment of network databases. In March 2000, Lucent announced that Q IP had been ranked as the market share leader for standalone Internet Protocol (IP) ad- dress management products. The product is used by prominent companies such as MCI Worldcom's UUNET, Discover Financial Services, Ford Motor Company, and others. See Quadritek. QJDP QIP/Windows 2000 Joint Developer Program. Lucent Technologies' initiative launched in Decem- ber 1999 to foster development of design interfaces and requirements between QIP 5.0 IP address man- agement software and Windows 2000. See QIP, Quadritek. QL See query language. QLLC See Qualified Logical Link Control. QMS Queue Management System. See queue man- agement. QoR See Query on Release. QoS See Quality of Service. QPL Qualcomm PureVoice Library. See Qualcomm Code Excited Linear Predictive Coding. QPSK 1. See quadrature phase shift keying. 2. See quaternary phase shift keying. QR queuing requirements. See queuing theory. QRP A designation for low-power amateur frequency radio transmissions. Low-power transmitters and re- ceivers are an interesting subgroup of hobbyist radio, when used with respect for the privacy of individu- als and within regulatory guidelines. Regulations for short distance, low-power transmissions are more lenient than for other types of broadcasts. QRP trans- mitters can be used for short-distance broadcasting, home security systems, door intercoms, climbing communicators, baby and child monitors, and other short-range projects. QRP ARCI The QRP Amateur Radio Club Interna- tional is a nonprofit organization dedicated to ama- teur design, construction, and use ofQRP (low power) transmitters. See Amateur Radio Relay League, QRP. http://www.qrparci.org/ QSAM see quadrature sideband amplitude modula- tion. QSDG See Quality of Service Development Group. QTAM See Queued Telecommunications Access Method. QTF See quartz tuning fork. QTC QuickTime Conference. See QuickTime. QTSS QuickTime Streaming Server. See QuickTime. QTVR QuickTime Virtual Reality. See QuickTime. QuAD Quorum Associate Distributor. See Quorum International. quad- Prefix for four. quad antennaA type of array antenna similar in prin- ciple to a Yagi-Uda antenna, except that it uses full- wavelength loops in the place of half-wavelength straight elements, thus providing greater gain over a similar Yagi-Uda antenna. As with many antennas, the feed is commonly 75-ohm coaxial cable. A two- element quad antenna is called a quagi. Quad antennas come in a variety of configurations with the elements mounted on a boom or radiating out like the support threads of a spider web. In one common configuration, the prominent features in- clude simple straight-pole elements mounted in a horizontal plane at right angles to one another with a diamond-shaped configuration on one pole mounted in the vertical plane. There are variations on quad antennas including cubical quads (which can re- semble an open umbrella with the fabric missing) and hybrid quads. Mini-quads - compact quad antennas - have some advantages that are appealing to amateur radio en- thusiasts including reasonable cost, low wind load- ing, and small turning radius. Quad/mini-quad anten- nas in the 15±5 m frequencies are readily available. Quad Integrated Communications Controller QICC (pron. qwik). A single-chip integrated CPU32+ microprocessor from Motorola designed for embed- ded telecommunications and internetwor~ing appli- cations. The MC68360 QICC is a next-generation MC68302 with four serial communications control- lers, two serial management controllers, and one se- rial peripheral interface that operates at 4.5 MIPS at 24 MHz. QICC is useful for controller applications. Quad International Communications Corpora- tion QICC. ACalifornia-based international supplier of telecommunications products including Frame Relay. quad wiring Wiring bundles consisting of four indi- vidually sheathed, untwisted wires brought together (aggregated) within a single cover. Quad wiring is ~:~~e~~~ir~rt~~e 1~~~i~~i~~ri:~~~\1;°~~f:r~~:~~~ III green and red (tip and ring) for the first line, and black and yellow for the second line. This type of wiring is not recommended for data transmission installations. Quad fiber cables consist of four individual fiber cables bundled together within a single cover. quadrature A state in which cyclic events are 90 degrees out of phase. In signal transmission quadra- ture, phasing is a common technique used to distin- guish information in signals. It is also used to vary a signal so crosstalk between two closely associated transmissions is reduced. quadrature amplitude modulation QAM. A modu- lation technique employing variations in signal am- plitude. This modulation scheme is used in asymmet- ric digital subscriber line services, for example. It is a two-dimensional coding scheme that can be trans- mitted in anarrower spectrum, a combination of am- plitude and phase-shift modulation. The QAM spec- trum derives from the spectrum of the baseband sig- nals as they apply to the quadrature channels. QAM is similar to nonreturn-to-zero baseband trans- mission and multiphase phase shift keying (PSK), except that QAM does not have a constant envelope as in PSK. QAM requires lower sampling frequencies and the spectral width can be optimized by keeping the baud rate lower, thus reducing the potential for crosstalk. See modulation. 779 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary quadrature/quadriphase phase-shift keying QPSK. A type of phase shift keying modulation scheme in which four signals are used, each shifted by 90°, with each phase representing two data bits per symbol, in order to carry twice as much informa- tion as binary phase shift keying (BPSK), which can be seen as two independent binary phase shift key (BPSK) systems. QPSK can be used to carry bit timing and can be fil- tered using raised cosine filters for out-of-band sup- pression. Even more sophisticated systems exist that employ differential encoding of symbol phases. Lin- ear power amplifiers are used with the various QPSK schemes. Staggered quadrature/quadriphase phase shift keying (SQPSK) is similar to QPSK except that the data channels are offset to shift the carrier 90°. The stag- gering facilitates recovery ofI and Q channels. See frequency modulation, frequency shift keying, on/off keying, modulation, quadrature sideband amplitude modulation. quadrature sideband amplitude modulation QSAM. A modulation encoding technique in which different signal amplitude states represent data. Quadritek Systems Inc. A network products firm founded in 1993 to provide server-related solutions. QIP is Quadritek's (IF) network address management software product. In March 1998, ffiM and Quadritek announced a col- laboration in which ffiM would make changes to its Dynamic Host Configuration Protocol (DHCP) and Domain Name Server (DNS) to enable Quadritek and other vendors to use an open standard API to man- age servers. Thus, Quadritek's QIP product could be used to manage multiple, distributed IBM DHCP/ DNS servers. Quadritek is now Lucent Technologies IPSPG. quadruplex circuitAcircuit which is carrying two bidirectional transmissions simultaneously to make a total of four. Qualcomm Code Excited Linear Predictive Cod- ing QCELP. A proprietary algorithm from Qual comm CDMA Technologies (QCT) that supports digital voice coding/decoding through code division multiple access (CDMA) methods. QCELP compres- sion supports fixed and variable encoding. In the mid-1990s, Qualcomm released the Pure Voice vocoder (voice coder), based on 13-kilobit QCELP for use in cellular and Personal Communications Sys- tem (PCS) products. The design goal of the Pure Voice vocoder was to provide voice quality approaching that of wire line while still keeping the bit rate as low as possible to work within the capacity limitations of mobile communications devices. Since it is a soft- ware solution, it can be integrated into a wide vari- ety of desktop and mobile devices. In 1998, Qualcomm announced an agreement with Apple Computer to integrate the Pure Voice QCELP- based audio codec technology into Apple's popular QuickTime multimedia software. The Pure Voice technology is popular because of its relatively high quality and small file size, which is significantly 780 smaller than audio files stored in .wav format, for example. Pure Voice was also adapted for use in email in the late 1990s, so users could send actual voice messages through computer networks such as the Internet. The excellent compression ratios inherent in the QCELP technology made this apractical application and en- abled greetings to be communicated without tradi- tional long-distance telephone charges. The PureVoice Player/Recorder and the PureVoice Con- verter are available online as licensed, freely distrib- utable software from Qualcomm Incorporated. Qualified Logical LinkControl QLLC. A data link control protocol from IBM which works with the ffiM SNA systems to allow them to operate over X.25 packet switched data networks. quality 1. Meeting subjective and/or objective stan- dards of excellence in operation, manufacture, aes- thetics, or a combination of these. 2. In manufactur- ing, quality is more narrowly defined as conformance to high objective standards of appropriateness, func- tionality, and longevity within the context ofrelated products. 3. In service industries, quality is generally determined by adherence to operating and ethical standards of the industry and degree of customer sat- isfaction. See quality assurance. quality assurance Systematic actions which seek to assure satisfactory levels of manufacture, service, functionality, and longevity. quality factor See Q factor. quality ofservice QoS. This has a general meaning across many industries and somewhat more specific meanings in telecommunications networks. Quality of service is aperformance descriptor and reference for the provision of services on a network. It includes parameters and values pertaining to data rates, accept- able delays, losses, errors, etc. As part of the QoS requirements for an ATM network, four class of service (CoS) traffic types have been specified: CoS Characteristics Class A Connection-oriented, constant bit rate (CBR), with a strong timing relationship between source and destination. Constant bit rate video and PCM encoded voice are included in this category. Class B Connection-oriented; bit rate may vary, with a strong timing relationship between source and destination. Class C Connection-oriented; bit rate varies, no timing relationship between source and destination. TCP lIP and X.25 are included in this category. Class D Connectionless; bit rate varies, no timing relationship between source and destination. Connectionless packet data are included in this category. © 2003 by CRC Press LLC There are many types of data, and how they are per- ceived in part determines how their quality is evalu- ated. Consequently, QoS requirements vary with the type of data. See cell rate, class of service. Quality ofService Development Group QSDG. A Telecommunication Standardization Sector group of the International Telecommunications Union estab- lished in 1984 to help develop practical implemen- tations of international telecommunication quality of service (QoS) standards. It is funded primarily by ad- ministrations and ROAs. quantizationA process in which a continuous range of values, such as an incoming analog signal, is sub- divided into ranges, with a discrete value assigned to each subset. This is a means of converting analog data to digital data, and is used in musical sound sampling, modem communications, voice over data networks, radio wave modulation, and many other aspects of telecommunications. Generally the frequency of the sampling influences the quality and fidelity of the outgoing quantized sig- nal, within certain limits set by the capabilities of the equipment and the characteristics of the human per- ceptual system. Higher sampling rates tend to pro- duce closer approximations to the original signal, but also require greater transmission speeds and band- width. Quantization is used in a number of modulation schemes, including pulse code modulation (PCM), which is commonly used in voice communications. See modulation, patches, pulse code modulation, sampling, quantization error. quantization,vectorA vector version of scalar quan- tization, designed to reduce the volume of data files or the bit rates of data transfers. Vector quantization has practical applications for image and speech coding. quantization error A number of aspects can intro- duce error into a quantized signal, including the amount of noise and interference accompanying the signal, the signal range or amplitude as it relates to the capabilities of the quantizing mechanism, the strength and complexity of the signal being quantized, and the mathematics used to carry out the conversion. Quantization error is sometimes assessed after a digi- tal signal is reconverted to analog fonnat, and the end signal is compared to the original, with the differences assessed subjectively (as in music systems) or evalu- ated with various measuring instruments. quantize To convert a continuous range of values into discrete, nonoverlapping values or steps. This is an important means to convert analog to digital values. quantizing distortion units QDU. A measure of the degree of degradation in a voice channel that occurs as a result of format and signal conversions (e.g., ana- log to digital to analog). This is described in the ITU- TG Series Recommendation G.tt3 (transmission im- pairments ). quantometer An instrument for the measurement of magnetic flux. quantum (plural - quanta, symb. - q) A relatively recently discovered and investigated phenomenon related to the movement of electrons. Quantum theory was first stated by physicist Max Planck in 1900. A quantum is a discrete quantity of electromagnetic energy (e.g., aphoton oflight energy), the smallest possible amount of energy at any given frequency v. Quantum phenomena are of great interest to physi- cists, and researchers are now investigating ways of enlisting quantum behaviors in the manufacture and use of various industrial products such as lasers and in operations associated with digital logic, with some surprising and provocative success. See Einstein, Albert; Planck, Max; quantum cascade laser. quantum cascade laser QC laser. A new type of ''NanoLaser'' developed by Frederico Capasso and Jerome Faist at Bell Laboratories in 1994. The QC laser is a continuously tunable, single-mode, distrib- uted- feedback device. To understand how a QC laser works, imagine an electric current stimulating a number of electrons to cascade over a series of steppes (a terraced organi- zation), squeezed through quantum wells in succes- sive layers, dropping off energy in the fonn of pho- tons (light pulses) as they contact and travel through each steppe. At each steppe, the electrons perform a quantum jump between well-defined energy levels. The photons emitted as a result of their activity re- flect back and forth in an amplification process that stimulates other quantum jumps and emissions and results in a high output. This process can be exploited by creating a corrugated grating layer within a semi- conductor which acts as a filtering device for specific wavelengths according to the grating period and, to some extent, the operating temperature. ~~~fsJi~d~a~:S:r~~~~d?:g~y;:g:;ti~:~r P~~~;. and finer linewidth in terms of the specificity of the wavelengths emitted. They can operate over a wide selection of wavelengths in the mid-infrared range from 3.4 - t7 J.lm. QC lasers can be used in many ap- plications, including medical diagnostics, radar het- erodyne detectors, production process control, and remote sensing applications - particularly environ- mental monitoring in toxic environments due to gas- sensing capabilities. The wavelength of the laser is determined by quan- tum confinement. Thus, it can be tuned selectively over a wide range of the infrared spectrum by vary- ing the layer thicknesses and spacing of the different materials used in its manufacture. This differs from other technologies in that the output wavelength is not dependent upon the chemical composition of the semiconductors, but upon their thickness and posi- tioning. These layers, created with a molecular beam epitaxy (MBE) materials-growth process, are some- times only a few atoms thick. The QC laser also func- tions at higher temperatures than traditional diode lasers, making it practical for room temperature use. See Capasso, Frederico; distributed-feedback laser; Fabry-Perot laser; quantum well; vertical-cavity sur- face-emitting laser. Quantum Corporation A prominent data storage device developer/distributor, founded in 1980. Quantum became well-known for computer hard drives in the 781 © 2003 by CRC Press LLC . description of the B-ISDNUser Part. {B-ISUP)ofSS7 Q.2762 B-ISDN-generalfunctions of messages and signals of the B-1 SUP of S87 Q.2763 B-ISDN - SS7 B-ISDN User Part (B- ISUP)-Formats and codes Q.2764 B-ISDN- 8S7 B-ISDN User Part (B- ISUP) -Basic call procedures Q.2765 B-ISDN S87 B-ISUP-Application Transport Mechanism (APM) Q.2931 B-ISDN-Digital. (OSS-2) Q.2660 B-ISDN- intemetworking between signaling SystemNo. 7 B-ISDNUser Part (B-ISUP) and N-ISDN User Part (N-ISUP) Q.2723 Extensions to SS7 B-ISDN User Part (B-1 SUP) Q.2725 B-ISDNUser Part. establishmentphase Q.2963 B-ISDN DSS-2 - extensions for ATM Q.2964 B-ISDNDSS-2 - basic look-ahead and other clauses Q.296S B-ISDN DSS-2 - Quality of Service (QoS) issues Q.2971 B-ISDN - digital subscn"ber DSS- 2- user