Fiber Optics Illustrated Dictionary street price The price paid for a product after shop- ping around, as opposed to suggested list or suggested retail, the price the wholesaler or manufacturer has designated for the product, which is usually higher due to dealer discounts. The suggested list price is often imprinted on the product packaging and over- laid with a lower dealer price. The street price may equal the dealer's price or may be a commonly ne- gotiated price; through discounts, volume, and com- petitive pricing, dealers often offer a street price much lower than the list price. The street price may also be higher than list price. For example, a ticket for a popu- lar rock concert sold by street hawkers an hour be- fore showtime may have a street price much higher than the original ticket price (the "scalped" price). stringed insulators Electrical insulating objects mounted in multiples in order to increase the spac- ing distance to what is needed between a conducting line and its supporting structure. Higher voltage lines mounted overhead on utility poles or high voltage towers tend to require a longer string of insulators that can be directed away from the pole or cross ann. The insulators are commonly strung in single rows or in a "y" configuration. Depending upon their configu- ration and the number ofstrings, it may be difficult to access and maintain stringed wires from cherry picker (bucket) maintenance vehicles. Climbers manually scaling utility poles with strung insulators must also be careful not to move within the minimum air distance (MAD) arcing zone, which is especially tight in Y configurations. The arcing zone is related to the length of the insulating string. See suspension insulator. stringing The process of running wire or cable, es- pecially as applied to stringing utility wires along outdoor utility poles. stringing block See stringing roller. stringing rope A narrow-gauge rope used to help string lines through narrow walls, conduits, or string- ing rollers. It is also called a pilot rope or pulling rope. The end of the line to be installed will be attached to the stringing rope and then pulled through the nar- row channel. For example,when threading a line up through the narrow vertical space in a wall from one floor to another, the stringing rope may be passed down from above, the line attached, and then the stringing rope pulled up again to feed or pilot the line through the wall or through a conduit pipe installed in the wall. If the stringing rope is used for above- ground utility line installation, the rope is used to pull conductive line through stringing rollers, over the track provided by the stringing sheaves that are the main part of the roller assembly. See stringing roller, stringing sock. stringing roller A device with a rolling indented wheel attachment called a sheave that facilitates stringing wires and cables by enabling the pulled cable to run smootWy along the track supplied by the rotating roller. Stringing rollers also often have vari- ous types of hooks or eye sockets for mounting or attachment. Stringing rollers are commonly designed so that they can be mounted on utility pole crossanns 892 or on vertical or horizontal insulators. Stringing roll- ers for outdoor use are typically made of materials that resist corrosion such as stainless steel and alu- minum alloys. They may also have neoprene liners. When attached to crossanns or insulators on outdoor utility poles, a stringing roller may require an addi- tional crossann or insulator adaptor. Auniversal stringing roller is a multipurpose roller designed with a number offittings and adaptors for mounting it in various positions on various types of supports. This type of roller may also need an addi- tional adapter when mounted on crossarms. A uni- versal roller makes it possible to purchase mass quan- tities, even if they are used for different types oflines and mounting surfaces. A distribution roller is a type of stringing roller in- tended to support multiple conductors. The roller is wider than a single stringing roller, with two or more side-by-side grooves to keep the conducting lines separated from one another as they pass over the roller. The distribution roller aids in managing mul- tiple line support with a minimum ofequipment and space. A boom truck roller is a specialized type ofstringing roller for temporary lifting and support of hot (elec- trically live) lines during maintenance, repair, or re- arrangement. It can be mounted on a crossarm or in- sulated boom, as needed, and removed after the work is complete. Stringing rollers are also called stringing blocks (as in block and tackle). They are generally sold with load ratings to support different types and gauges ofwires and cables. There are occupational regulations on the stringing of conductive lines. For example, under OSHA regu- lations, ifa conductor or pulling line is pulled by an automated device, the lineworker is not permitted to be directly under the roller or on the crossarm, ex- cept as is necessary to guide a stringing sock through the stringing roller's sheave. See sheave. stringing sock A device used with a stringing rope to enable it to attach to and pull multiple conductive lines through piloting by a single stringing line. It is sometimes also called a stringing board, depending upon its design. stringing tool A tool designed to enable a single util- ity pole lineworker to transfer the conductive line from a stringing roller to a clamp (preferably one- handed) in such a way that the roller doesn't have to be removed. See stringing roller. strip To remove the outer protective layers such as jackets, annoring, and sleeves, usually to reveal a conductive core. In electrical wiring, a protective plastic jacket that prevents shock and environmental interference or damage is typically stripped from ends to be wound or soldered together to provide ajoint. In fiber optic cables, protective sheathing is stripped to add tenninators or to provide an unimpeded end for cleaving, polishing, and fusing. Specialized strip- ping tools are available for either of these applications. With fiber optic cable it is especially important to avoid nicking or scratching the filament. Use a © 2003 by CRC Press LLC non-nicking tool intended for filament stripping and don't slide the cutting/stripping tool along the fiber filament unless it is specially designed to be used this way. Scratches could interfere with light transmis- sion. After cutting the jacket, it should be gently tugged off the end of the fiber. If there is resistance against removal, cut closer to the end and remove the sleeve in sections (with as few cuts as possible). If there are several protective layers, they are often stripped one layer at a time, especially if they are made of different materials that require different types of cutters/strippers. stripped insulatorA conductive line insulator, as on a utility pole or tower, that has had the protrusions broken off, usually the outer skirt. This may happen as a result of aging, lightning strikes, or vandalism (e.g., target practice). stripping, image assembly In traditional page lay- out and printing, the process of positioning page com- posites, in the fonn of negatives or positives, on a flat in preparation for creating the printing plate. strobe n. 1. High speed intermittent illumination. 2. Older term for an electronic flash. 3. In asynchro- nous communication, input of parallel data to a reg- ister or counter. 4. A momentary intensified sweep ofa beam on, for instance, a scope. 5. On a computer bus, strobe lines indicate when data are being trans- ferred. Stromberg-Carlson Telephone Manufacturing Company Founded in 1894 by Alfred Stromberg and Androv Carlson, who took advantage of the oppor- tunity created by the expiration of the Bell patents to establish a competing phone company. Within 20 years, Stromberg-Carlson had become a leading in- dependent telephone company. After acquisition by the Home Telephone Company, it moved to New York in 1904. During World War I, the company supplied communications equipment to the military. The company subsequently introduced new materi- als into telephone construction, including Bakelite, a type of hard plastic. Around this time, the company was involved in consumer radio products and broad- casting, as well. It was FRC-licensed out of Roches- ter, New York, to operate station WHAM . A number of innovators in telephone technology worked for the company in the 1930s and 1940s, no- tably Andrew W. Vincent, who left in 1946 to develop an improved dial telephone system. As television technology evolved, the company pro- vided consumer TV sets, many of which are now collector's items. In 1955, Stromberg-Carlson was merged into General Dynamics, a major defense con- tractor and, in 1984, was acquired by Comdial Cor- poration, which remains committed to telecommu- nications products. strontium Sr. A soft element (AN 38) with a high refractive index and optical dispersion characteristics. It is used to fabricate glass for display devices. Strowger,Almon B. (1830-1902) An American mor- tician and inventor who created the first commercially viable automatic telephone switching system, a step- by-step switch patented in 1889 and a dial-switch patented in 1891. This system enabled a subscriber to dial-connect a local call without going through a human operator. The first Strowger exchange was es- tablished in Indiana in 1892. Strowger cofounded Automatic Electric in 1901, the largest telephone equipment manufacturer servicing Bell's competitors, the independent telephone com- panies. This was a successful fit, since Bell was cre- ating its own switching technology, such as the panel switch, in competition with Strowger's technology; also, the Strowger switch was somewhat unmanage- able in large installations, a limitation that was only a minor problem when the majority of Automatic Electric's customer base was small independent tele- phone companies. See Callender, Romaine; Lorimer, George and James; Strowger switch. Strowger switch The first automatic telephone switch put into commercial service, in Indiana, pat- ented in 1889 by Almon B. Strowger. Thus, direct dialing was born, and a human switchboard operator was no longer needed for connecting local calls. This also promoted a small revolution in phone design, since now dials were needed for callers to dial their own calls. The Strowger technology was further de- veloped and put into service by the Automatic Elec- tric company, cofounded by Strowger and directed by Alexander E. Keith. Surprisingly, the Bell system did not adopt the S trowger system until 20 years af- ter its introduction. See Callender switch, Lorimer switch, panel switch, step-by-step switch. Structure of ManagementInformationA standard for object naming and describing mechanisms for the purpose of network management. See RFC 1155. STS See shared tenant services. STSK Scandinavian Committee for Satellite Tele- communications. STU Secure Telephone Unit. A telephone designed to include cryptographic protection for voice, data, and fax transmissions. STU-3 Secure Telephone Unit 3. A secure telephone unit used for government communications. See STU. stump cam See cam, stump. STUN serial tunnel. Sturgeon,William Credited with producing the frrst electromagnet in 1823. SU See subscriber unit. Submarine Fiber Optics Communications Systems A newsletter published monthly by Information Gatekeepers Inc. (IGI) to provide market intelligence on new developments in undelWater fiber optic tech- nology, markets, and applications. SubmarineTelegraph CompanyApioneerLondon- based undelWater cable-laying firm known for some of the earliest marine telegraph cable installations. It was descended from the English Channel Submarine Telegraph Company founded by the brothers Brett in 1847. Using lead to weigh down the cable, an initial cable was installed between England and France in August 1850. However, cable capacitance was not fully understood at the time and the transmission was poor and oflittle use. In addition to this, the problem of boat anchors in the relatively shallow strait resulted 893 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary in the cable being severed. The company reformed into the Submarine Telegraph Company and a new deadline for connecting France to the British Isles was established. In September 1851, the company laid a functional underwater cable between Dover, England, and Calais, France. Over the next decade, it installed ad- ditional cables, totaling almost 900 miles of commu- nications links. The success of these historic cable installations was based in part upon the use of gutta- percha as an insulating material for preventing salt water corrosion to sealed transmission lines. In 1863, Cyrus Field, the promoter for the first successful transatlantic cable, contacted the company regarding the duration of their cables, to which John W. Brett responded with details as to their duration, extent, and locations. See Field, Cyrus West. Subnetwork Access Protocol SNAP. An evolution of the Logical Link Control (LLC) method, with backward compatibility with Ethernet, which facili- tates communication of entities at a given network layer. SNAP was developed by IEEE to support mul- tiple-standard, public and private Network Layer pro- tocols. SNAP expanded 8-bit SAP space to 40-bit (5 byte) protocol ill, and uses the first 5 bytes in the LLC Protocol Data Unit (PDU). SNAP supports more up- per-layer protocols than previous methods. It also allows Ethernet protocol type numbers to be used in IEEE 802 frames, to provide easy translation between Ethernet and IEEE 802 frames. subscriber loop The circuit between the telephone company's central office and the subscriber station. In earlier times, the subscriber station extended all the way to the phone, but more recently this demar- cation point has been changed to the service box out- side or inside the premises to which the interior wir- ing usually attaches. It's still possible to get service right to the telephone; it just costs more. SubscriberNetwork Interface SNI. One of the two interface ports of XA-SMDS systems used to con- nect an end user to the SMDS network. The other in- terface is the Intercarrier Interface (ICI). See Ex- change Access SMDS. subscriber unit SUo The device or system at the end ofa circuit. This may be a phone, handset, or com- puter terminal. substation A facility or piece of equipment that of- fers less in some way than a main station within a network of stations. In other words, it may have a smaller physical size, lower capacity, fewer units, a smaller staff, lower priority, etc. In electrical facilities, a substation is a high-voltage electrical switching facility used to supply lines, cir- cuits, and generators within a larger system. The sub- station may serve a local community, act as a relay station, and convert voltages from one level to another or from one type to another (e.g., AC to DC). Electrical substations are common in the industrial landscape. They usually have high fences, safety standoffs, and signs to warn the public of the dan- gers of injury or death from electrical shocks. In multiple phone systems, a substation is a phone Subscriber Loop - Telephone System srATIOIY -;4- STA TIOIY -s- 1 This historic schematic diagram shows the basic layout of a telephone common battery system with two subscriber lines in contact with one another through a manually operated cordboardswitchboard. 894 © 2003 by CRC Press LLC console that is subordinate to the main console. It typically has more limited buttons, features, or callout capabilities than the main console. In cases where the substation has the same capabilities as the main con- sole, the distinction is based more on where the call is initially directed (to the main console), with the substation only receiving the call when it has been redirected from the main console or another substation. substrate-incident recording SIR. A recording mechanism used in standard magneto-optical record- ing in which a transparent substrate is laid down over the recording layer. The laser light aimed at the re- corded layer when it is being read passes through the substrate. The substrate helps protect the recording layer from fingers, abrasions, oxidation, dust, etc. that would interfere with the recorded data. This substrate makes it possible for media like CDs to be picked up and moved around, in contrast to hard drives, in which the recording surface cannot be touched or moved wi thout damaging the media. The substrate coating on optical discs has some disadvantages as well. Be- cause the laser light must pass through an extra layer, there is a limit to the size, at the lower end of the scale, which can be used, thus limiting the resolution of the disc in terms of data density per unit area. Contrast with air-incident recording. See overcoat-incident recording. sulfur A yellow, brittle element (AN 16) occurring naturally in and around thermally active phenomena such as hot springs and volcanoes. It is found in gyp- sum, barite, epsom salts, and iron pyrites. Sulfur has many uses. It is a component of explosive chemicals, sulfuric acid, and is used to vulcanize rubber. SUMAC SuperHIPPI Media Access Controller. See HIPPI-6400. Sumitomo Electric Industries,Ltd. SEI. A Japanese firm specializing in the manufacture and distribution of electrical and optical wires and cables, founded in 1897. In 2002, SEI announced at the Optical Fiber Cmmunication Conference that it had developed a record-breaking fiber in terms of low loss character- istics, with attenuation of only 0.151 dB/km at a wavelength of 1568 nm. Sun Microsystems Computer Company SMCC. A California hardware and software manufacturer es- tablished in 1982, Sun's computer systems are com- monly found in higher educational institutions, sci- entific research and medical imaging applications, and as servers for local area networks (LAN s) in cor- porations, educational institutions, and Internet Ser- vices Provider (ISP) premises. Many ofSun's prod- ucts are aimed at telecommunications applications for voice and data. The company's products cover a wide range from desktop systems to high-end research and supercomputing systems. The SunOS and Solaris operating systems are well known. In 1996, Sun acquired Integrated Micro Products (IMP), including their fault-tolerant computer specifi- cally targeted to the telecommunications industry, and Cray Research's high-end server system. Sun's JavaSoft is the developer of the well-known Java object-oriented, platform-independent, general purpose programming language. JavaSoft collabo- rated with Lucent Technologies to develop a Java te- lephony application programming interface as part of a series of Java Media APIs to provide an open frame- work for Java applications development. Sun Microsystems Inc. and Motorola Inc. 's Multime- dia Group joined forces to develop products for cable operators to deliver high-speed data communications and Internet access to the home through Motorola's CyberSURFRTM cable modem. Sun's XTL Teleservices for Solaris is a set of telephony software services and open application programming interfaces that extend Solaris LIVE, an integrated multimedia environment. SunXTLAteleservices product delivery vehicle de- veloped by Sun Microsystems, known as Sun XTL Teleservices Platform for Solaris. SunXTL provides Teleservices development support for applications intended to run on personal workstations. The types of teleservices which can be implemented with this technology include integrated voice mail, ~nswering machine, automated dialing, faxing, etc. Because these are generated within the computing environ- ment, they can be integrated with input and output from word processors, address books, databases, and spreadsheets. SunXTL is a foundation library for telecommunica- tions-related applications, which includes call con- trol functions, data stream access methods, and data flow control. SunXTL API A SunXTL Teleservices object-ori- ented applications programming interface which fa- cilitates development ofpersonal desktop applica- tions with C++, including on-screen phone graphi- cal user interfaces, remote workstation access, per- sonal voice mail, etc. for telephony hardware periph- erals. SunXTL Call Objects The SunXTL API provides developers with C++ XtlCall objects to control vari- ous aspects ofa telephone call, including querying the call state and the numbers associated with the call, the call's current status, and its data type or media class. It can also request a change in call state. The XtlCall objects also have callback methods for the asynchronous notification of state changes. SunXTL Provider Configuration Database The SunXTL Teleservices configuration database is a re- pository for installed providers. The database pro- vides information on each provider and how to in- voke it, and lists its characteristics and capabilities. The database describes telephony resources such as available bandwidth, number of available lines, types of voice services available, etc. A graphical user in- terface (GUI) tool xtltool is provided for browsing and editing the Provider Configuration Database. SunXTLProviderInterfaceA SunXTL Teleservices open interface providing third-party developers and Independent Hardware Vendors (IHVs) with a way to use the Provider library to ensure compatibility and compliance with basic system protocols. This mes- sage set can be extended with user-specific features. The provider interface fits between the server and/or 895 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary datastream multiplexer and the various drivers. SunXTL Provider LibraryAsunXTL Teleservices library which works with the Provider Interface to keep the Provider information distinct from system services. The library provides interfaces to various data streams and services, including the Provider da- tabase and various server functions. SunXTL Server The SunXTL Teleservices server provides administration, message passing, and secu- rity to networked personal workstations running SunXTL Teleservices applications. SunXTL System Services The sunXTL Teleservices System Services provide an intermediary between the application view ofa call object and the provider's implementation of the call. Interprocess message passing, object identification and creation, call own- ership, and security are handled by the server. Super DLTtape SDLT. A tape data format developed by the Quantum DLTtape Group that provides reli- able high-capacity storage at good transfer rates. The format is competitive with the linear tape-open (LTD) format. Search and data rate speeds are similar, with LTD slightly faster and SDLTwith slightly higher ca- pacity (currently about 10% more). SDLT is based upon magneto-resistive heads densely packed into clusters that are joined in an advanced thin-film medium, resulting in higher capacity and faster transfer rates than traditional magneto-resistive technologies. Advanced Metal Powder (AMP) ma- terials enable small, smoothly coated particles with higher densities to be packed into the medium. In addition to the physical properties of the technology, SDLT uses partial response/maximum likelihood (pRML) data-handling techniques, further increasing capacity and performance. Developers have mapped out four generations of SDLT technology with predicted capacities of more than a terabyte of data on a single cartridge: Generation 1 SDLT drives backward-read- compatible with existing DLT products, released in March 2000 and fourth quarter 2001 support- ing capacities of 110 and 160 Gbytes at transfer rates of 11 and 16 MBps. Ultra2 and Ultra 160 SCSI, LVD, and HVD interface support. Generation 2 SDLT 640 planned for release in 2003, with backward-read capability, increased capacity, and Ultra320 SCSI and Fibre Channel interface support. Planned capacity of 3200 GBytes at 32 MBps. Generation 3 SDLT 1280 planned for release in 2005, with backward-read capability and the in- tention to support emerging or prevalent inter- faces at the time of release. Planned capacity of 640 GBytes at 50+ MBps. Generation 4 SDLT 2400 planned for release in 2006, with backward-read capability and support for prevalent or emerging technologies at time of release. Planned capacity of 1.2 TBytes at 100+ MBps Given the dramatic increases in hard drive capacity in 2001, backup technologies such as tape cartridges 896 have become especially important. See Advanced Metal Powder, linear tape-open, partial response/ maximum likelihood. super server A high end server which consists ofa number of computers networked together with com- munications links that are as fast, nearly as fast, or faster than the processing speed ofanyone individual computer, so the collection functions as a fast, inte- grated, distributed, unified entity. With very fast trans- missions media and protocols like HIPPI and SuperHIPPI, the distinction between individual ma- chines becomes less critical, and the processing al- gorithms for carrying out the tasks are more crucial to the concept of the system as an organism. A super server can also be a single machine with multiple CPU s, set up to function together to handle higher- end processing requests at faster speeds, or of greater complexity than might be achieved with a typical one- CPU system. A number of interesting distributed pro- cessing supercomputing applications have been con- figured at several U.S. research labs using Linux on personal computers communicating through fast net- work links. Super Speed CallingA telephony subscriber option, which is essentially the same as Speed Calling in that it allows an abbreviated set of characters to be dialed to invoke a longer number. The distinction is more ofa marketing distinction to describe enhanced sys- tems where a name can be entered, which is easier to remember, rather than just a number (usually four digits or characters). See abbreviated dialing. Super Video See S- Video. super video graphics array SVGA. A graphics stan- dard common on IBM and licensed third-party com- puters, supporting a variety of palettes and resolu- tions, including 800 x 600; 1024 x 768; 1280 x 1024; 1,600 x 1,200; 1024 x 768 (16 or 256 colors). See video graphics array. supercomputing A term applied to high-end com- puting applications provided on the best hardware/ software available at any particular state of the tech- nology. Supercomputers originated sometime in the 1950s, when the viability of computers as a commercial item became apparent. Some of the earliest supercom- puters were designed by IBM and shipped in the early 1960s. The supercomputers of 30 years ago had fewer ca- pabilities and were slower than many handheld cal- culators of today, (they were also much larger in physical size). The definition of supercomputing is thus a relative one, since most desktop computer sys- tems now are faster and more powerful than main- frames running multiuser networks in many univer- sities and colleges 15 years ago. Supercomputers tend to be characterized by faster (or multiple) CPUs, wider data buses, faster network links, and larger, faster-access storage devices than those available as consumer products. They also may be run with more sophisticated distributed processing algorithms, al- though writing parallel applications is an art and much research and discovery is yet to be done. © 2003 by CRC Press LLC Supercomputers tend to be used in scientific research and military applications. superframe In its generic sense, superframe is used to describe a period in time during which a specified number of downstream and upstream frames are transmitted. Thus, the transmission time of a super- frame will be related to the bit rate. The concept of the superframe is used in the context of frame timing and alignment. SuperFrame standard SF. A 1969 improvement to the original 1962 DS-l standard for a frame format for 1.544 Mbps transmissions (2.048 in Europe with 30 channels) which improves the signal-to-noise ra- tio and combines 12 frames into one SuperFrame. Frames 6 and 12 are used for robbed-bit signaling. This has since been superseded by Extended Super- Frame, which provides increased error detection and removes the need to take down an entire line for ser- vicing. See Extended SuperFrame. supergroup In analog voice phone systems, a hier- archy for multiplexing has been established as a se- ries of standardized increments. See voice group for chart. See jumbogroup for a diagram. superheterodyne receiverAn early improvement in radio receivers designed to be more sensitive than radio frequency receivers of the time. The superhet- erodyne receiver incorporated a signal detector work- ing in conjunction with a local oscillator to mix the signals, producing an intermediate frequency which was then amplified and passed on to a second detec- tor, and from there to the earpiece. The superhetero- dyne circuit was invented by the "Father of FM," Edwin Howard Armstrong. See heterodyne. SuperHIPPI See HIPPI-6400. SuperHouse A trademark of Bell South, to signify a house designed with information services resources built in (conduit, wiring, etc.) to support computing and Internet applications. This is often called a "smart house" and, in fact, SmartHouse has been trade- marked by the National Society of Home Builders. SuperJANET See JANET. superparamagnetic Phenomena which contribute to magnetization and signal decay of magnetically recorded information over time, thus limiting the useful lifespan of magnetic recording media. The density of recording information is related to the superparamagnetic effects as well, resulting in a prac- tical superparamagnetic limit. Studies for arranging magnetic data in particle array systems to study super- paramagnetic effects to develop practical schemes and optimize recording density are being carried out at the ffiM Research labs. superpose 1. To place or layover, with or without contact with that which is overlaid. 2. To overlay upon another such that all like parts of the overlay coincide with the overlaid. superposition principle A principle which can be applied to networked electrical circuits to solve current values in individual branches of the network. See Kirchoff's laws. SupersparrowA wide area Web setver load-balancing system (LBS) distributed as open-source software under a GNU Public License. Supersparrow, based on Border Gateway Protocol (BGP), was developed by Simon Horman and initially released in Decem- ber 2000. Supersparrow aids in distributing Web access to avail- able servers on the Internet. In many circumstances, users are given the option to select mirror sites that include the same content stored on servers that may be faster or geographically closer to the user. Mirror sites are an especially welcome option to high-traf- fic primary sites. However, users have traditionally had to select a static mirror site manually from a list of Web links. It's time-consuming to read the lists and stats and sometimes difficult to determine the most promising option. Often some of the links are unavail- able or the addresses out of date. Supersparrow aims to effectively automate the process ofutilizing mir- ror sites using BGP to determine an efficient data path (least-cost path). BOP was selected because it has in- formation on efficient paths to points on the Internet and provides for failure recovery. Unlike the Linux Virtual Server (LVS), Supersparrow does not require a single contact point for incoming traffic. Supersparrow is compatible with VA Linux servers and can accommodate connections to Apache Web servers. See load-balancing system. superstation A television broadcast station whose signal reaches a very wide audience by being retrans- mitted beyond what would be possible by standard ailWaves. The extended viewing area is often reached by a satellite transmission further extended through cable. supertrunkA high-end data transmissions cable sys- tem which carries multiple high-bandwidth services such as several video channels. surf colloq. A common term for riding a wave, a tech- nology, a trend, or other force or medium. Channel surfing describes a television watcher who uses a remote control device to skim programs from chan- nel to channel, particularly during commercials. This is done with the hope of finding better programming (or as thumb exercises for couch potatoes). Surfing the Net means to travel, in the virtual sense, through the myriad resources and sites on the Internet, espe- cially through the Web, a graphical interface to the Internet. See browser, Internet, World Wide Web. surface plasmon resonance SPR. A quantum electro-optical effect resulting from the interaction of light with a metal surface. At a specific resonant wavelength equal to the quantum energy ofplasmons ( electron packets), photon energy is transferred to the plasmons. SPR is a form of total internal reflectance (TIR) oc- curring at the interface between materials with dif- fering refractive indexes. If a thin conducting film is placed between two optical media, surface plasmons in the film will couple resonantly with matching light frequencies. The resonance wavelength can be cal- culated by measuring the light reflected by the metal surface. Under conditions of resonance reflection, incident light is absorbed rather than reflected. See reflectometer, total internal reflection. 897 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary surface-array recording SAR. A process for access- ing both sides of an optical disc simultaneously through independent read-write heads on both sides of the disc. By using simultaneous access by the read- write heads, rather than one or the other at one time, companies like Maxoptix (which has trademarked Surface Array Recording) have realized almost double the transfer rate and disc capacity of previ- ous products. Thus, unlike some previous optical media devices (laserdisc players), users need not flip over the media to read the second side. See air-inci- dent recording, overcoat-incident recording, sub- strate- incident recording. surge Large, sudden changes in a circuit current or voltage. See burst. surge protector, surge suppressor A device that conditions or filters electrical current to reduce power fluctuations. It is placed where it can provide protec- tion to subsequent devices or components in a sys- tem. Ground lines are sometimes used to drain off the surge. Surge protectors may be built into abuilding's electrical system to drain off surges from voltage spikes or lightning strikes. Some limited protection from lightning storms may be possible with a consumer surge protector, but a direct hit will likely damage the protector and inter- connected systems. Surge protectors are recom- mended for laptops that get plugged into circuits ofa dubious nature (motel or ferryboat sockets, etc.). suspension insulator A type of high-voltage utility pole insulator patented by F. Locke in 1905. The sus- pension insulator was supported out and away from the pole or crossarm with wires rather than mounted on the top of the pole or on a crossbar. Sometimes more than one suspension insulator was mounted on a single pole. Historic Locke insulators were rigid fixtures screwed to a porcelain disc. Locke used eye hooks in a later 1910 patent. Locke's ideas were re- fined and improved over the years and suspension insulators became an important means to increasing the level of power that could be transmitted across overhead utility poles. There were problems, however; suspension insula- tors with ceramic or cement cap-and-pin designs were heavy and high maintenance; they tended to deterio- rate quickly. Thus, later suspension insulators were simpler, all-metal designs (though still relatively heavy), consisting of a series of spaced insulating rings protected by larger arcing rings to protect from electrical surges (e.g., lightning strikes). See strain insulator. sustainable cell rate SCR. In ATM networking, the upper measure of a computed average rate of cell transmission over time. See the Appendix for ex- panded explanations of ATM. SUT 1. System Under Test. See ATM. 2. Service User Table. A telephone use authorization term. SVC See switched virtual connection. SVD simultaneous voice and data. SVGA See Super Video Graphics Array. SVHS, SuperVHS, SuperiorVideo HomeSystem A video recording and playback standard introduced 898 in 1987 by JVC for the high-end consumer (pro- sumer) markets. The format was intended to be less expensive than commercial systems but significantly better quality than the VHS format widespread at the time. SVHS is downwardly compatible with VHS. VHS tapes can be recorded on SVHS systems, but not the reverse, as the image signal differs (audio is handled in the same way as VHS). The SVHS tapes have holes in them to enable record/playback equip- ment to recognize the cassette as SVHS. SVHS more nearly represents the resolution of tele- vision broadcast signals and thus retains the clarity of the image far better than VHS. With a higher ini- tial resolution, SVHS is also more suitable for video editing as less detail is lost in copying. At the time SVHS was introduced, consumer VHS decks were in the $199 to $600 range, whereas SVHS sold in the $500 to $2000 range, a little expensive for the average consumer, but attractive to those with professional aspirations and limited budgets. SVHS is a 1/2-in. tape format that was less expensive than the 3/4-in. formats that dominated the commercial in- dustry at the time of its release and SVHS gradually found a niche, especially with videophiles using desk- top video systems such as the NewTek/ Amiga Video Toaster. By 2000, the cost of consumer SVHS decks had dropped to below $200, with TBC-equipped versions selling for under $500. At this point the fonnat be- came very popular for desktop video and multime- dia editing for the Web. Hi-8mm/8mm camcorders that have recently become popular usually have S-Video output ports. See Hi-8mm, S-Video. Swelling Tape in Fiber Optic Cable Swelling tape may be incorporated into fiber optic cables, especially those installed outdoors in humid areas, particularly if freezing occurs that might dam- age sensitivefiberfilaments. In this assembly, the com- ponents include coatedopticalfibers (1), swelling tape (2), water-resistant tubing (3), a supporting strain relief layer, usually of aramid yarn (4), one or more rip cords to facilitate the un peeling of the cable for making connections (5), a reinforcing strength mem- ber (e.g., steel), andthe outer sleeve (7). SVHS-C, Super VHS-Compact A compact (small format) version ofSVHS designed to be used in por- table devices such as camcorders. The image quality is higher than VHS, but the tape recording times are shorter than a standard cassette. In general, SVHS-C began to be overshadowed by Sony-developed Hi- 8mm formats offering the benefits of small size, high quality, and longer tape recording times. Neverthe- less, JVC continues to support and improve upon the SVHS-C product line, introducing digital options © 2003 by CRC Press LLC such as time-lapse and still shots. Standard 45-minute VHS-C can be used in lVC SVHS-C units. See SVHS. swelling tape A tape used in cable assemblies to pre- vent water interference or damage to the inner con- ductive materials. Swelling tape may be semi- conductive or nonconductive and both may be used in a single cable assembly in different layers of the assembly (usually with intervening layers). It is used in a variety of types of cables, especially outdoor cables, including power and fiber optic cables (power cables may have more than one swelling tape layer). switch n. 1. A mechanical, electrical, or optical de- vice that breaks or completes a path in a circuit, or changes the path. In fiber optic networks, consider- able effort has been expended on developing optical switches to reduce the energy conversion and loss that occurs in hybrid optical/electrical switch systems. Bell Labs is one of the research centers delving into this area, with some success in developing optical switches based upon micro-electromechanical sys- tems (MEMS) technologies. See switch, optical; switcher. 2. An electronic circuit designed to carry out a logic operation. New switches have capabili- ties that were once found only in routers, and some can do switching at the application level (fourth layer). 3. In software, a means to direct a routine; a branch. switch hook See hook switch. Fiber Optic Communications Switch 40 14 10~ Apatentedfiberopticswitchingapparatusproposed by Rosete et ale in October 2000 to provide a direct means to switch signals on or off without lenses or stepping motors. An electrical charge applied to the electromagnet influences the switching member (24) and causes the ends of the connectingfibers (13 and 15) housed in the V-groove to come out of alignment, thus switching to an off state. Alternately, if two V- grooves are alignedone above the other, thefiber (12) can switch between to inputs (or outputs). [USPTO patent diagram.} switch, opticalA means to break, divert, or complete a transmission path through optical rather than electro- mechanical components. Optical switches are often favored for optical networks to reduce the amount of energy conversion and loss that may occur in hybrid networks. Bell Labs has developed a MEMS-based optical switch with response times below 70 Jls using a mir- ror connected to an electrostatically-activated seesaw driven by a flat plate. Electrically stimulating the plate causes it to pull down and displace the mirror result- ing in two states in which the optical signal can pass through or is deflected. By using a spectral grating to demultiplex the wavelengths and direct them to an array of mirrors, an optical add/drop multiplexer can be devised. Historic Manual Communications Switch This historic telephone switchboard cordboard shows thejacks and receptacles which were manually connected to complete a circuitbetween the callerand callee. Indicator lights helped operators keep track of calls in progress. switchboard In its most general sense, any device into which a number of incoming and outgoing cir- cuits are routed, where the routing of the individual circuit connections can be changed manually, me- chanically, or electronically. Human-operated telephone cordboards are probably the most picturesque of the various historic switch- ing boards. The earliest ones required that a foot pedal be pumped to generate the power to ring the subscriber's phone. A manual telephone cordboard was often built into a wall, and was hand-connected with simple jacks and cables. In early telephone his- tory, young men were hired to staff switchboards, as women were not permitted to work in most clerical positions, but the arrangement had problems. Some of the male employees were rude to callers, chewed tobacco while talking, and used excessive profanity. As a result, in the mid-1880s, women were hired, and eventually replaced men entirely until the late 1970s when a few male operators re-entered the field. 899 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary Most male and female switchboard operators are now being replaced by automated switchboard systems with voice recognition and touchtone menu dialing functions. The large panels of switch connections in early cordboards and switchboards have been replaced by multiline phone consoles in many businesses, al- though some large phone installations or central switching services still have wall panels. Even here, human receptionists are becoming rare, with many small businesses adopting computer voicemail ser- vices instead. See Coy switchboard. switchboard cable This has two meanings. It was originally a patch cable used in old manual cordboard telephone systems to patch two circuits together to create the end-to-end connection for a phone call. Now that manual switchboards have been replaced by automated switching systems, the switchboard cable is considered to be the one which connects a central office switchboard with an associated auto- mated system, such as a computer. Switched S6 The name ofa 56-Kbps switched net- work voice/data service provided by some local tele- phone companies which allows cal1s among several points through one-pair or two-pair copper wires. Switched 56 can be used for voice, file transfers, In- ternet access, facsimiles, connections to other local area networks, and videoconferencing. This service is gradually being superseded by ISDN services. See DS-O. Switched Multi-Megabit Digital Service SMDS. A high-speed wide area networking (WAN), con- nectionless, packet-switched cell relay transport ser- vice based on IEEE 802.6, offered by telephone ser- vice providers. It provides capabilities to intercon- nect LANs (Ethernet, Token-Ring, etc.) and WANs through public switched telephone networks (PSTNs). SMDS can be integrated with transmission technolo- gies such as ISDN, DS-x, and Frame Relay with as- sociated bandwidths ranging from 56 or 64 kbps to 34 Mbps or more. It works with asynchronous, syn- chronous, and isochronous data and can be used over optical fiber. It can provide congestion control to pro- tocols such as Frame Relay, which don't have con- gestion control as an intrinsic part oftheir specifica- tion or implementation. See cyclic reservation mul- tiple access. switched virtual connection, switched virtual cir- cuit SYC. A generic term for a logical communica- tions connection. InATM systems, there are two types of SYCs: switched virtual path connection (SVPC) and switched virtual channel connection (SYCC). SYC provides on-demand connections between com- municating end systems. Using signaling software, the Yirtual Path IdentifierNirtual Channel Identifier (VPINCI) information will be dynamically allocated to the participating end systems. Switched Voice Service SYS. The standard service offered with FTS2000. See FTS2000. switcher An audio/video component that provides easy reconfiguration of several circuits. In a sense, 900 the button on the receiver that enables selecting CD, phono, or tape is a switcher, although the meaning is more often ascribed to a separate component with a number ofconnectors, inputs, and outputs. See AlB switchbox, switch. switching There are three types of switching com- monly used in telecommunications networks: mes- sage switching, circuit switching, and packet switch- ing. In message switching, the entire message is re- layed, intact, through a variety of nodes or service points, from the sender to the recipient. Circuit switch- ing is commonly used in end-to-end direct communi- cations, as in telephone connections. Packet switch- ing involves the segmentation, routing, and reassem- bly ofcommunications so different parts of the mes- sages may be transmitted at different times and through different routes. While this may not sound very efficient, it is an excellent way to manage data in a large, dynamic, distributed environment, and pro- vides many possibilities for data sharing, represen- tation, authentication, and filtering as desired. The Internet is built upon packet switching concepts. See circuit switching, packet switching, switch. switching simulation The simulation on a computer, usually with graphical output, of the circuitry and operations ofa switching system. Hayward and Bader did early computer simulations oftelephone switch- ing networks in 1955. SWR See standing wave ratio. SXGA super-extended graphics array. symbol Acharacter, icon, or other agreed-on abbre- viated representation, useful in representing objects, quantities, languages, arithmetic and logic operations, rules, layout schemes, qualities, sounds, ideas, and others. Examples of symbols include street signs, logos, musical notes, electronics diagram elements, computer buttons and icons, words, punctuation marks, and arithmetic operators. symbolic Representative of something else, or of some greater meaning, usually in an abbreviated form. See symbol. symbolic code A computer code which represents programs in source language, with symbolic names and addresses, in contrast to machine code, which has hardware-specific names and addresses. Use of mne- monic symbols in higher level languages aids in pro- gramming and debugging, and symbolic names and addresses can be used to increase portability to other platforms. See assembly language. symbolic debugger An essential software program- ming and debugging tool used to control and moni- tor applications under development. A debugger fa- cilitates stepping through execution of the code, set- ting breakpoints and temporary branches, determin- ing and changing the contents ofvariables, and view- ing the design and functionality of software-in- progress. A symbolic debugger eases the task of find- ing code segments (many current software applica- tions have tens of thousands and even hundreds of thousands of lines of code) by jumping to a symbol, such as a label name, to avoid searching through cryptic code. © 2003 by CRC Press LLC symbolic language A computer programming language that uses mnemonic symbols, rather than machine code or actual hardware names and addresses, in or- der to make the process of creating the code more comfortable for humans and easier to read and de- bug. See symbolic code. symbolic logic A written symbol language developed to express logical and mathematical concepts and ar- guments in a way that is more specific to itself and less ambiguous than natural human languages. sync advancerA video component for resolving hori- zontal and burst phase signals for multiple camera signals with different characteristics due to cabling. In video, where signal pulse timing is important for combing signals, pulse discrepancies can arise from simple things like cables of uneven lengths, some- times even resulting in delays that must be resolved before further processing the signals. sync separatorA video device for taking a compos- ite video input and deriving the characteristics of the signal (such as composite sync, vertical sync, hori- zontal sync, back porch, field, ill) so that the signal can be processed to synchronize with other video components. For example, a synch separator can be used to provide loop-through viewing from a cam- era to a monitor while synching the camera feed to another component. The sync separator provides the pulses required by other components and mayor may not be genlockable. Different models are available for positive-going or positive-going video (or both). See genlock, negative-going video. synchronize 1. To cause to occur at the same instant in time. 2. To precisely match two waves or two func- tions. 3. To assess the characteristics of an input sig- nal and process it to conform to characteristics ex- pected by a receiving link/component. 4. To assess the characteristics of two or more input signals and process them to conform to timing, pulse, or other characteristics in order to form a single signal or multiple signals with compatible characteristics. synchronous Signals with the same timing reference and the same frequency. See isochronous, asynchronous. Synchronous Data Link Control SDLC. In IBM Systems Network Architecture (SNA) systems, SDLC is a bit-oriented, link-level protocol that pro- vides a means of moving data between Network Ad- dressable Units (NAUs). The Data Link Control layer lies between the higher layers and the Physical Con- trollayer and communications links, and passes in- fonnation through. SDLC is a subset of the High-level Data Link Con- trol (HDLC) protocol. SDLC is packet-oriented, with each frame compris- ing a header, infonnation, and trailer. It transparently provides flow control, multipoint addressing, error detection, and muItimessage capabilities. See Sys- tems Network Architecture. Synchronous Digital Hierarchy SDH. A fiber op- tics transmission technology for efficient transport of digital signals. Different versions of SDH are defined; those used within North America and Japan and those used in Europe and elsewhere. The North American version of this general technol- ogy is called SONET and is standardized by the American National Standards Institute (ANSI). SDH standards are coordinated by the International Tele- communications Union (ITV-T) and published pri- marilyas G Series Recommendations documents. See G Series Recommendations, SONET. Synchronous Optical Network See SONET. Syncom-4 Communications Satellite The Syncom IV-4 communications satellite as it is released from the payload bay of the Space Shuttle Discovery. It was deployed from the Shuttle with a disc toss motion in August 1985. [NASA image} Syncom 3 The first geostationary satellite, designed for telecommunications use, launched on 19 August 1964 by the United States. syntax 1. The rules ofstructure or grammar for a lan- guage, natural or computer. 2. In programming, the words and symbols valid within the structure and scope ofa computer language. syntax error An error in a programming statement which indicates an unrecognized word, symbol, or structure. Syntax errors are usually flagged and dis- played by debuggers and compilers so that the error can be corrected. See syntax. synthesized voice Amechanically or electronically generated speaking system. Synthesized voices are now used on phone systems, computers, and certain public address systems. The voice may be constructed from recordings ofnatural human voices, pieced to- gether electronically from sound samples, or may be entirely synthetic. See speech synthesis. Syslog Protocol A Berkeley Software Distribution (BSD) protocol that provides service options related to the propagation of event messages over a network; Syslog Protocol has now been ported to other oper- ating systems as well. The protocol was submitted as an Information RFC by C. Lonvick in August 2001. Syslog messages may have varying content in vary- ing format, since they originate on a number of types ofplatfonns. Syslog services originate, are relayed, and are received in device, relay, or collector modes. A sender transmits a message without knowledge of whether the next leg is a relay or recipient. Acollector 901 / :.','.','." It ir © 2003 by CRC Press LLC . by CRC Press LLC Fiber Optics Illustrated Dictionary surface-array recording SAR. A process for access- ing both sides of an optical disc simultaneously through independent read-write heads on both sides of the disc. By using simultaneous access by the read- write heads, rather than one or the other at one time, companies like Maxoptix (which has trademarked Surface. third-party developers and Independent Hardware Vendors (IHVs) with a way to use the Provider library to ensure compatibility and compliance with basic system protocols. This mes- sage set can be extended with user-specific features. The provider interface fits between the server and/or 895 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary datastream multiplexer and the various drivers. SunXTL. level to another or from one type to another (e.g., AC to DC). Electrical substations are common in the industrial landscape. They usually have high fences, safety standoffs, and signs to warn the public of the dan- gers of injury or death from electrical shocks. In multiple phone systems, a substation is a phone Subscriber Loop - Telephone System srATIOIY -; 4- STA TIOIY -s- 1 This historic