1.
Modular connector
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A modular connector is an electrical connector that was originally designed for use in telephone wiring, but has since been used for many other purposes. Many applications that used a bulkier, more expensive connector have converted to modular connectors. Probably the most well known applications of modular connectors are for telephone jacks and for Ethernet jacks, Modular connectors were originally used in the Registration Interface system, mandated by the Federal Communications Commission in 1976 in which they became known as registered jacks. The registered jack specifications define the wiring patterns of the jacks, instead, these latter aspects are covered by ISO standard 8877, first used in ISDN systems. TIA/EIA-568 is a standard for data circuits wired on modular connectors, other systems exist for assigning signals to modular connectors, physical interchangeability of plugs and jacks does not ensure interoperation, nor protection from electrical damage to circuits. For example, modular cables and connectors have used to supply low-voltage AC or DC power. Modular connectors also go by the names modular phone jack/plug, RJ connector, the term modular connector arose from its original use in a novel system of cabling designed to make telephone equipment more modular. This includes the 4P4C handset connector, a very popular use of 8P8C today is Ethernet over twisted pair, and that may be the most well known context in which the name RJ45 is known, even though it has nothing to do with the RJ45 standard. Likewise, the 4P4C connector is sometimes called RJ9 or RJ22, Modular connectors were originally developed and patented by General Cable Corp in 1974. They replaced the hard-wired connections on most Western Electric telephones around 1976, at the same time, they began to replace screw terminals and larger 3 and 4 pin telephone jacks in buildings. Modular connectors have gender, plugs are considered to be male, while jacks or sockets are considered to be female, plugs are used to terminate loose cables and cords, while jacks are used for fixed locations on surfaces such as walls and panels, and on equipment. Other than telephone extension cables, cables with a plug on one end. Instead, cables are connected using an adapter, which consists of two female jacks wired back-to-back. Modular connectors are designed to latch together, a spring-loaded tab on the plug snaps into a jack so that the plug cannot be pulled out. To remove the plug, the latching tab must be depressed, the standard and most common way to install a jack in a wall or panel is with the tab side down. This usually makes it easier to operate the tab when removing the plug, because the person grabs the plug with thumb on top, the modular connector suffers from a design flaw or weakness however, as the fragile latching tab easily snags on other cables and breaks off. When this happens, the connector is still functional, but the crucial latching feature is lost, some higher quality cables have a flexible sleeve called a boot over the plug, or a special tab design, to prevent this. These cables are marketed as snagless
2.
Twisted pair
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It was invented by Alexander Graham Bell. In balanced pair operation, the two wires carry equal and opposite signals, and the destination detects the difference between the two and this is known as differential mode transmission. Noise sources introduce signals into the wires by coupling of electric or magnetic fields, the noise thus produces a common-mode signal which is canceled at the receiver when the difference signal is taken. This problem is especially apparent in telecommunication cables where pairs in the same cable lie next to each other for many miles, one pair can induce crosstalk in another and it is additive along the length of the cable. Twisting the pairs counters this effect as on each half twist the wire nearest to the noise-source is exchanged, providing the interfering source remains uniform, or nearly so, over the distance of a single twist, the induced noise will remain common-mode. Differential signaling also reduces electromagnetic radiation from the cable, along with the associated attenuation allowing for greater distance between exchanges, the twist rate makes up part of the specification for a given type of cable. When nearby pairs have equal twist rates, the conductors of the different pairs may repeatedly lie next to each other. For this reason it is specified that, at least for cables containing small numbers of pairs. In contrast to shielded or foiled twisted pair, UTP cable is not surrounded by any shielding, UTP is the primary wire type for telephone usage and is very common for computer networking, especially as patch cables or temporary network connections due to the high flexibility of the cables. The earliest telephones used telegraph lines, or open-wire single-wire earth return circuits, in the 1880s electric trams were installed in many cities, which induced noise into these circuits. Lawsuits being unavailing, the telephone companies converted to balanced circuits, as electrical power distribution became more commonplace, this measure proved inadequate. Two wires, strung on either side of cross bars on utility poles, within a few years, the growing use of electricity again brought an increase of interference, so engineers devised a method called wire transposition, to cancel out the interference. In wire transposition, the wires exchange position once every several poles, in this way, the two wires would receive similar EMI from power lines. This represented an early implementation of twisting, with a twist rate of about four twists per kilometre, such open-wire balanced lines with periodic transpositions still survive today in some rural areas. Twisted-pair cabling was invented by Alexander Graham Bell in 1881, by 1900, the entire American telephone line network was either twisted pair or open wire with transposition to guard against interference. UTP cables are found in many Ethernet networks and telephone systems, for indoor telephone applications, UTP is often grouped into sets of 25 pairs according to a standard 25-pair color code originally developed by AT&T Corporation. A typical subset of these colors shows up in most UTP cables, for urban outdoor telephone cables containing hundreds or thousands of pairs, the cable is divided into small but identical bundles. Each bundle consists of twisted pairs that have different twist rates, the bundles are in turn twisted together to make up the cable
3.
Ethernet
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Ethernet /ˈiːθərnɛt/ is a family of computer networking technologies commonly used in local area networks, metropolitan area networks and wide area networks. It was commercially introduced in 1980 and first standardized in 1983 as IEEE802.3, over time, Ethernet has largely replaced competing wired LAN technologies such as token ring, FDDI and ARCNET. The original 10BASE5 Ethernet uses coaxial cable as a medium, while the newer Ethernet variants use twisted pair. Over the course of its history, Ethernet data transfer rates have increased from the original 2.94 megabits per second to the latest 100 gigabits per second. The Ethernet standards comprise several wiring and signaling variants of the OSI physical layer in use with Ethernet, systems communicating over Ethernet divide a stream of data into shorter pieces called frames. As per the OSI model, Ethernet provides services up to, since its commercial release, Ethernet has retained a good degree of backward compatibility. Features such as the 48-bit MAC address and Ethernet frame format have influenced other networking protocols, the primary alternative for some uses of contemporary LANs is Wi-Fi, a wireless protocol standardized as IEEE802.11. Ethernet was developed at Xerox PARC between 1973 and 1974 and it was inspired by ALOHAnet, which Robert Metcalfe had studied as part of his PhD dissertation. In 1975, Xerox filed a patent application listing Metcalfe, David Boggs, Chuck Thacker, in 1976, after the system was deployed at PARC, Metcalfe and Boggs published a seminal paper. Metcalfe left Xerox in June 1979 to form 3Com and he convinced Digital Equipment Corporation, Intel, and Xerox to work together to promote Ethernet as a standard. The so-called DIX standard, for Digital/Intel/Xerox, specified 10 Mbit/s Ethernet, with 48-bit destination and source addresses and it was published on September 30,1980 as The Ethernet, A Local Area Network. Data Link Layer and Physical Layer Specifications, version 2 was published in November,1982 and defines what has become known as Ethernet II. Formal standardization efforts proceeded at the time and resulted in the publication of IEEE802.3 on June 23,1983. Ethernet initially competed with two largely proprietary systems, Token Ring and Token Bus, in the process, 3Com became a major company. 3Com shipped its first 10 Mbit/s Ethernet 3C100 NIC in March 1981, an Ethernet adapter card for the IBM PC was released in 1982, and, by 1985, 3Com had sold 100,000. Parallel port based Ethernet adapters were produced for a time, with drivers for DOS, by the early 1990s, Ethernet became so prevalent that it was a must-have feature for modern computers, and Ethernet ports began to appear on some PCs and most workstations. This process was sped up with the introduction of 10BASE-T and its relatively small modular connector. Since then, Ethernet technology has evolved to meet new bandwidth, in addition to computers, Ethernet is now used to interconnect appliances and other personal devices
4.
Category 5 cable
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Category 5 cable, commonly referred to as Cat 5, is a twisted pair cable for carrying signals. This type of cable is used in structured cabling for computer networks such as Ethernet, the cable standard provides performance of up to 100 MHz and is suitable for 10BASE-T, 100BASE-TX, 1000BASE-T, and 2. 5GBASE-T. Cat 5 is also used to other signals such as telephony. This cable is connected using punch-down blocks and modular connectors. Most Category 5 cables are unshielded, relying on the balanced twisted pair design. Category 5 was superseded by the Category 5e specification, and later category 6 cable, the specification for category 5 cable was defined in ANSI/TIA/EIA-568-A, with clarification in TSB-95. These documents specify performance characteristics and test requirements for frequencies up to 100 MHz, cable types, connector types and cabling topologies are defined by TIA/EIA-568-B. Nearly always, 8P8C modular connectors are used for connecting category 5 cable, the cable is terminated in either the T568A scheme or the T568B scheme. The two schemes work equally well and may be mixed in an installation so long as the scheme is used on both ends of each cable. Each of the four pairs in a Cat 5 cable has differing precise number of twists per meter to minimize crosstalk between the pairs, although cable assemblies containing 4 pairs are common, category 5 is not limited to 4 pairs. Backbone applications involve using up to 100 pairs and this use of balanced lines helps preserve a high signal-to-noise ratio despite interference from both external sources and crosstalk from other pairs. The cable is available in both stranded and solid conductor forms, the stranded form is more flexible and withstands more bending without breaking. Permanent wiring is solid-core, while patch cables are stranded, the specific category of cable in use can be identified by the printing on the side of the cable. Most Category 5 cables can be bent at any radius exceeding approximately four times the diameter of the cable. The maximum length for a segment is 100 m per TIA/EIA 568-5-A. If longer runs are required, the use of hardware such as a repeater or switch is necessary. The specifications for 10BASE-T networking specify a 100-meter length between active devices and this allows for 90 meters of solid-core permanent wiring, two connectors and two stranded patch cables of 5 meters, one at each end. The category 5e specification improves upon the category 5 specification by revising and introducing new specifications to further mitigate the amount of crosstalk
5.
10 Gigabit Ethernet
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10 Gigabit Ethernet is a group of computer networking technologies for transmitting Ethernet frames at a rate of 10 gigabits per second. It was first defined by the IEEE802. 3ae-2002 standard, half duplex operation and repeater hubs do not exist in 10GbE. Like previous versions of Ethernet, 10GbE can use either copper or fiber cabling, however, because of its bandwidth requirements, higher-grade copper cables are required, category 6a or Class F/Category 7 cables for lengths up to 100 meters. The 10 Gigabit Ethernet standard encompasses a number of different physical layer standards, a networking device, such as a switch or a network interface controller may have different PHY types through pluggable PHY modules, such as those based on SFP+. At the time that the 10 Gigabit Ethernet standard was developed, the WAN PHY encapsulates Ethernet packets in SONET OC-192c frames and operates at a slightly slower data-rate than the local area network PHY. Over the years the Institute of Electrical and Electronics Engineers 802.3 working group has published several standards relating to 10GbE, to implement different 10GbE physical layer standards, many interfaces consist of a standard socket into which different PHY modules may be plugged. Physical layer modules are not specified in a standards body. Relevant MSAs for 10GbE include XENPAK, XFP and SFP+, when choosing a PHY module, a designer considers cost, reach, media type, power consumption, and size. A single point-to-point link can have different MSA pluggable formats on either end as long as the 10GbE optical or copper port type inside the pluggable is identical, XENPAK was the first MSA for 10GE and had the largest form factor. X2 and XPAK were later competing standards with smaller form factors, X2 and XPAK have not been as successful in the market as XENPAK. XFP came after X2 and XPAK and it is also smaller, the newest module standard is the enhanced small form-factor pluggable transceiver, generally called SFP+. Based on the small form-factor pluggable transceiver and developed by the ANSI T11 fibre channel group, it is smaller still, SFP+ has become the most popular socket on 10GE systems. SFP+ modules do only optical to electrical conversion, no clock and data recovery, SFP+ modules share a common physical form factor with legacy SFP modules, allowing higher port density than XFP and the re-use of existing designs for 24 or 48 ports in a 19 rack width blade. Optical modules are connected to a host by either a XAUI, XENPAK, X2, and XPAK modules use XAUI to connect to their hosts. XAUI uses a data channel and is specified in IEEE802.3 Clause 48. XFP modules use a XFI interface and SFP+ modules use an SFI interface, XFI and SFI use a single lane data channel and the 64b/66b encoding specified in IEEE802.3 Clause 49. SFP+ modules can further be grouped into two types of host interfaces, linear or limiting, limiting modules are preferred except when using old fiber infrastructure which requires the use of the linear interface provided by 10GBASE-LRM modules. There are two classifications for optical fiber, single-mode and multi-mode, in SMF light follows a single path through the fiber while in MMF it takes multiple paths resulting in differential mode delay
6.
Ethernet over twisted pair
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Ethernet over twisted pair technologies use twisted-pair cables for the physical layer of an Ethernet computer network. Early Ethernet had used various grades of coaxial cable, but in 1984 and this led to the development of 10BASE-T and its successors 100BASE-TX and 1000BASE-T, supporting speeds of 10,100 and 1,000 Mbit/s respectively. All these three standards define both full-duplex and half-duplex communication, however, half-duplex operation for gigabit speed isnt supported by any existing hardware. All these standards use 8P8C connectors, and the cables from Cat3 to Cat8 have four pairs of wires, though 10BASE-T, the Institute of Electrical and Electronics Engineers standards association ratified several versions of the technology. The first two designs were StarLAN, standardized in 1986, at one megabit per second, and LattisNet, developed in January 1987. Both were developed before the 10BASE-T standard and used different signalling, in 1988 AT&T released StarLAN10, named for working at 10 Mbit/s. The StarLAN10 signalling was used as the basis of 10BASE-T, the centralized star topology was a more common approach to cabling than the bus in earlier standards and easier to manage. Using point-to-point links instead of a shared bus greatly simplified troubleshooting and was prone to failure. Exchanging cheap repeater hubs for more advanced switching hubs provided an upgrade path. Mixing different speeds in a single network became possible with the arrival of Fast Ethernet, depending on cable grades, subsequent upgrading to Gigabit Ethernet or faster may be as easy as replacing the network switches. The common names for the standards derive from aspects of the physical media, the leading number refers to the transmission speed in Mbit/s. BASE denotes that baseband transmission is used, the T designates twisted pair cable, where the pair of wires for each signal is twisted together to reduce radio frequency interference and crosstalk between pairs. Where there are standards for the same transmission speed, they are distinguished by a letter or digit following the T, such as TX, referring to the encoding method. Twisted-pair Ethernet standards are such that the majority of cables can be wired straight-through and it is conventional to wire cables for 10- or 100-Mbit/s Ethernet to either the T568A or T568B standards. The terms used in the explanations of the 568 standards, tip and ring, refer to older communication technologies, and equate to the positive and negative parts of the connections. A 10BASE-T or 100BASE-TX node such as a PC uses a connector wiring called medium dependent interfaces, transmitting on pin 1 and 2, an infrastructure node accordingly uses a connector wiring called MDI-X, transmitting on pin 3 and 6 and receiving on pin 1 and 2. These ports are connected using a cable, so each transmitter talks to the receiver on the other side. Nodes can have two types of ports, MDI or MDI-X, hubs and switches have regular ports
7.
TIA/EIA-568
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ANSI/TIA-568 is a set of telecommunications standards from the Telecommunications Industry Association. The standards address commercial building cabling for telecommunications products and services, as of 2017, the standard is at revision D, replacing the 2009 revision C,2001 revision B, the 1995 revision A, and the initial issue of 1991, which are now obsolete. Perhaps the best known features of ANSI/TIA-568 are the pin/pair assignments for eight-conductor 100-ohm balanced twisted pair cabling and these assignments are named T568A and T568B. An IEC standard ISO/IEC11801 provides similar standards for network cables, ANSI/TIA-568 was developed through the efforts of more than 60 contributing organizations including manufacturers, end-users, and consultants. Work on the standard began with the EIA, to standards for telecommunications cabling systems. EIA agreed to develop a set of standards, and formed the TR-42 committee, the work continues to be maintained by TR-42 within the TIA, EIA is not longer in existence and hence EIA removed from the name. The first revision of the standard, TIA/EIA-568-A. 1-1991 was released in 1991, the standard was updated to revision B in 1995. The demands placed upon commercial wiring systems increased dramatically over this due to the adoption of personal computers and data communication networks. The development of twisted pair cabling and the popularization of fiber optic cables also drove significant change in the standards. These changes were first released in a revision C in 2009 which has subsequently replaced by the D series. ANSI/TIA-568 defines structured cabling system standards for buildings, and between buildings in campus environments. The main standard, ANSI/TIA-568. 0-D defines general requirements, while ANSI/TIA-568-C.2 focuses on components of balanced twisted-pair cable systems, ANSI/TIA-568. 3-D addresses components of fiber optic cable systems, and ANSI/TIA-568-C.4, addressed coaxial cabling components. The intent of these standards is to provide recommended practices for the design and installation of cabling systems that support a wide variety of existing. Developers hope the standards provide a lifespan for commercial cabling systems in excess of ten years. This effort has been successful, as evidenced by the definition of category 5 cabling in 1991. Thus, the process can reasonably be said to have provided at least a nine-year lifespan for premises cabling. All these documents accompany related standards that define commercial pathways and spaces, residential cabling, administration standards, grounding and bonding, the standard defines categories of unshielded twisted pair cable systems, with different levels of performance in signal bandwidth, insertion loss, and cross-talk. Generally increasing category numbers correspond with a cable system suitable for higher rates of data transmission, Category 3 cable was suitable for telephone circuits and data rates up to 16 million bits per second
8.
Telecommunications Industry Association
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The Telecommunications Industry Assocs most widely adopted standards include, TIA-942 Telecommunications Infrastructure Standard for Data Centers TIA-568-C. TIA is a standards organization of the ITU-T Global Standards Collaboration initiative. The TIA2012 is Conference & Exhibition, scheduled for June 5–7 at the Gaylord Hotel in Dallas, Texas, focused on innovation and thought leadership, TIA2012 is the annual gathering of the community of technology suppliers that form the foundation of the global communications experience. TIA2012 is the annual community gathering of all who create, distribute and use network technologies, network engineers and designers, product managers. TIA Now is a media outlet of TIA that informs about ICT trends, event. They interview top level executives and thought leaders that shape the development of the information and communication industry ICT and it delivers a perspective on policy, industry news, new technologies and evolving business strategies designed to inform and educate an audience of ICT decision-makers
9.
ISO/IEC 11801
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It covers both balanced copper cabling and optical fibre cabling. The standard was designed for use within commercial premises that may consist of either a building or of multiple buildings on a campus. It was optimized for premises that span up to 3 km, up to 1 km2 office space, Class F features even stricter specifications for crosstalk and system noise than Class E. To achieve this, shielding has been added for individual wire pairs, besides the shield, the twisting of the pairs and number of turns per unit length increases RF shielding and protects from crosstalk. The Category 7 cable standard has been created to allow 10 Gigabit Ethernet over 100 m of copper cabling, the cable contains four twisted copper wire pairs, just like the earlier standards. Category 7 cable can be terminated either with 8P8C compatible GG45 electrical connectors which incorporate the 8P8C standard or with TERA connectors, when combined with GG-45 or TERA connectors, Category 7 cable is rated for transmission frequencies of up to 600 MHz. Category 7 is not recognized by the TIA/EIA, Class FA channels and Category 7A cables, introduced by ISO11801 Edition 2 Amendment 2, are defined at frequencies up to 1000 MHz, suitable for multiple applications including CATV. Each pair offers 1200 MHz of bandwidth, simulation results have shown that 40 Gigabit Ethernet may be possible at 50 meters and 100 Gigabit Ethernet at 15 meters. In 2007, researchers at Pennsylvania State University predicted that either 32 nm or 22 nm circuits would allow for 100 Gigabit Ethernet at 100 meters. Category 8 should be fully compatible with Category 6A and below. As of January 2014, draft versions of ISO/IEC TR 11801-99-1, the final specifications will depend on transceiver requirements to be defined by IEEE802. 3bq workforce. Annex E, Acronyms for balanced cables, provides a system to specify the exact construction for both unshielded and shielded balanced twisted pair cables, european standard EN50173, Information technology — Generic cabling systems
10.
Electromagnetic interference
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The disturbance may degrade the performance of the circuit or even stop it from functioning. In the case of a path, these effects can range from an increase in error rate to a total loss of the data. Both man-made and natural sources generate changing electrical currents and voltages that can cause EMI, automobile ignition systems, mobile phones, thunderstorms, the Sun, and it can also affect mobile phones, FM radios, and televisions. EMI can be used intentionally for radio jamming, as in electronic warfare, in 1933, a meeting of the International Electrotechnical Commission in Paris recommended the International Special Committee on Radio Interference be set up to deal with the emerging problem of EMI. CISPR subsequently produced technical publications covering measurement and test techniques and recommended emission and these have evolved over the decades and form the basis of much of the worlds EMC regulations today. Test methods and limits were based on CISPR publications, although similar limits were already enforced in parts of Europe, one of these was the EMC Directive and it applies to all equipment placed on the market or taken into service. Its scope covers all apparatus liable to cause electromagnetic disturbance or the performance of which is liable to be affected by such disturbance and this was the first time there was a legal requirement on immunity, as well as emissions on apparatus intended for the general population. Many countries now have similar requirements for products to some level of Electromagnetic Compatibility regulation. Electromagnetic interference can be categorized as follows, Narrowband EMI or RFI interference typically emanates from intended transmissions, such as radio, broadband EMI or RFI interference is unintentional radiation from sources such as electric power transmission lines. Conducted electromagnetic interference is caused by the contact of the conductors as opposed to radiated EMI. Electromagnetic disturbances in the EM field of a conductor will no longer be confined to the surface of the conductor and this persists in all conductors and mutual inductance between two radiated electromagnetic fields will result in EMI. Interference with the meaning of electromagnetic interference, also radio-frequency interference is – according to Article 1, for lower frequencies, EMI is caused by conduction and, for higher frequencies, by radiation. EMI through the wire is also very common in an electrical facility. Newer radio systems incorporate several improvements that enhance the selectivity, in digital radio systems, such as Wi-Fi, error-correction techniques can be used. Spread-spectrum and frequency-hopping techniques can be used with analogue and digital signalling to improve resistance to interference. A highly directional receiver, such as an antenna or a diversity receiver. In the United States, the 1982 Public Law 97-259 allowed the Federal Communications Commission to regulate the susceptibility of electronic equipment. Electromagnetic interference at 2.4 GHz can be caused by 802. 11b and 802. 11g wireless devices, Bluetooth devices, baby monitors and cordless telephones, video senders, and microwave ovens
11.
Ground loop (electricity)
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In an electrical system, a ground loop or earth loop is an equipment and wiring configuration in which there are multiple paths for electricity to flow to ground. Ground loops are a cause of noise, hum, and interference in audio, video. In any case the difference between the ground terminals of each item of equipment is small. A severe risk of electric shock occurs when equipment grounds are removed in an attempt to cure the problems thought to be caused by ground loops. This only becomes a problem when one or more cables are then connected between A and B, to pass data or audio signals from one to the other. The shield of the cable is typically connected to the grounded equipment chassis of both A and B. There is now a ground loop, the ground loop will be carrying some current at the local supply frequency, typically 50 Hz or 60 Hz, due to electromagnetic induction from current-carrying conductors nearby. There is an AC magnetic field everywhere in developed areas, however, its magnitude and this influences the current induced in the ground loop, which is also dependent on the area enclosed by the ground loop and its orientation. The impedance of the loop, basically just its resistance at low frequencies and it is important to realise that for a ground loop to cause problems, there must be a local magnetic field produced by power frequency or other systems. It is the combination of radiated field and receptive ground loop that causes problems, in effect, the ground loop is the secondary of a very loosely coupled transformer, the primary being the summation of all current carrying conductors nearby. Transformer action limits the voltage in the loop, and the weak coupling limits the maximum current that will flow. Again, the voltage is not relevant, inside a building, the wiring may include radiating loops, e. g. It has been alleged that a significant cause of current in the loop is voltage drop along the equipment protective ground conductors. This is rarely significant, because safety regulations place strict limits on ground leakage current, the current arising due to magnetic induction is liable to be at least one or two orders of magnitude greater. So, when a current is induced in the loop, there will be a drop along the signal ground return. This is directly additive to the signal, and will result in objectionable hum. This is a significant fraction of the voltage of a moving coil pickup cartridge. Therefore there is no current loop, and no hum problem due directly to the grounding arrangements, careless interconnection is virtually guaranteed to result in hum problems
12.
Category 5e
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Category 5 cable, commonly referred to as Cat 5, is a twisted pair cable for carrying signals. This type of cable is used in structured cabling for computer networks such as Ethernet, the cable standard provides performance of up to 100 MHz and is suitable for 10BASE-T, 100BASE-TX, 1000BASE-T, and 2. 5GBASE-T. Cat 5 is also used to other signals such as telephony. This cable is connected using punch-down blocks and modular connectors. Most Category 5 cables are unshielded, relying on the balanced twisted pair design. Category 5 was superseded by the Category 5e specification, and later category 6 cable, the specification for category 5 cable was defined in ANSI/TIA/EIA-568-A, with clarification in TSB-95. These documents specify performance characteristics and test requirements for frequencies up to 100 MHz, cable types, connector types and cabling topologies are defined by TIA/EIA-568-B. Nearly always, 8P8C modular connectors are used for connecting category 5 cable, the cable is terminated in either the T568A scheme or the T568B scheme. The two schemes work equally well and may be mixed in an installation so long as the scheme is used on both ends of each cable. Each of the four pairs in a Cat 5 cable has differing precise number of twists per meter to minimize crosstalk between the pairs, although cable assemblies containing 4 pairs are common, category 5 is not limited to 4 pairs. Backbone applications involve using up to 100 pairs and this use of balanced lines helps preserve a high signal-to-noise ratio despite interference from both external sources and crosstalk from other pairs. The cable is available in both stranded and solid conductor forms, the stranded form is more flexible and withstands more bending without breaking. Permanent wiring is solid-core, while patch cables are stranded, the specific category of cable in use can be identified by the printing on the side of the cable. Most Category 5 cables can be bent at any radius exceeding approximately four times the diameter of the cable. The maximum length for a segment is 100 m per TIA/EIA 568-5-A. If longer runs are required, the use of hardware such as a repeater or switch is necessary. The specifications for 10BASE-T networking specify a 100-meter length between active devices and this allows for 90 meters of solid-core permanent wiring, two connectors and two stranded patch cables of 5 meters, one at each end. The category 5e specification improves upon the category 5 specification by revising and introducing new specifications to further mitigate the amount of crosstalk
13.
John Wiley & Sons
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Founded in 1807, Wiley is also known for publishing For Dummies. As of 2015, the company had 4,900 employees, Wiley was established in 1807 when Charles Wiley opened a print shop in Manhattan. Wiley later shifted its focus to scientific, technical, and engineering subject areas, Charles Wileys son John took over the business when his father died in 1826. The firm was successively named Wiley, Lane & Co. then Wiley & Putnam, the company acquired its present name in 1876, when Johns second son William H. Wiley joined his brother Charles in the business. Through the 20th century, the company expanded its activities, the sciences. Since the establishment of the Nobel Prize in 1901, Wiley and its companies have published the works of more than 450 Nobel Laureates. Wiley in December 2010 opened an office in Dubai, to build on its business in the Middle East more effectively, the company has had an office in Beijing, China, since 2001, and China is now its sixth-largest market for STEM content. Wiley established publishing operations in India in 2006, and has established a presence in North Africa through sales contracts with academic institutions in Tunisia, Libya, and Egypt. On April 16,2012, the announced the establishment of Wiley Brasil Editora LTDA in São Paulo, Brazil. Wileys scientific, technical, and medical business was expanded by the acquisition of Blackwell Publishing in February 2007. Through a backfile initiative completed in 2007,8.2 million pages of content have been made available online. Other major journals published include Angewandte Chemie, Advanced Materials, Hepatology, International Finance, launched commercially in 1999, Wiley InterScience provided online access to Wiley journals, major reference works, and books, including backfile content. Journals previously from Blackwell Publishing were available online from Blackwell Synergy until they were integrated into Wiley InterScience on June 30,2008, in December 2007, Wiley also began distributing its technical titles through the Safari Books Online e-reference service. On February 17,2012, Wiley announced the acquisition of Inscape Holdings Inc. which provides DISC assessments and training for interpersonal business skills. On August 13,2012, Wiley announced it entered into an agreement to sell all of its travel assets, including all of its interests in the Frommers brand. On October 2,2012, Wiley announced it would acquire Deltak edu, LLC, Deltak is expected to contribute solid growth to both Wileys Global Education business and Wiley overall. Seventh-generation members Jesse and Nate Wiley work in the companys Professional/Trade and Scientific, Technical, Medical, and Scholarly businesses, respectively. Wiley has been owned since 1962, and listed on the New York Stock Exchange since 1995, its stock is traded under the symbols NYSE, JW. A and NYSE
14.
International Standard Book Number
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The International Standard Book Number is a unique numeric commercial book identifier. An ISBN is assigned to each edition and variation of a book, for example, an e-book, a paperback and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, the method of assigning an ISBN is nation-based and varies from country to country, often depending on how large the publishing industry is within a country. The initial ISBN configuration of recognition was generated in 1967 based upon the 9-digit Standard Book Numbering created in 1966, the 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108. Occasionally, a book may appear without a printed ISBN if it is printed privately or the author does not follow the usual ISBN procedure, however, this can be rectified later. Another identifier, the International Standard Serial Number, identifies periodical publications such as magazines, the ISBN configuration of recognition was generated in 1967 in the United Kingdom by David Whitaker and in 1968 in the US by Emery Koltay. The 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108, the United Kingdom continued to use the 9-digit SBN code until 1974. The ISO on-line facility only refers back to 1978, an SBN may be converted to an ISBN by prefixing the digit 0. For example, the edition of Mr. J. G. Reeder Returns, published by Hodder in 1965, has SBN340013818 -340 indicating the publisher,01381 their serial number. This can be converted to ISBN 0-340-01381-8, the check digit does not need to be re-calculated, since 1 January 2007, ISBNs have contained 13 digits, a format that is compatible with Bookland European Article Number EAN-13s. An ISBN is assigned to each edition and variation of a book, for example, an ebook, a paperback, and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, a 13-digit ISBN can be separated into its parts, and when this is done it is customary to separate the parts with hyphens or spaces. Separating the parts of a 10-digit ISBN is also done with either hyphens or spaces, figuring out how to correctly separate a given ISBN number is complicated, because most of the parts do not use a fixed number of digits. ISBN issuance is country-specific, in that ISBNs are issued by the ISBN registration agency that is responsible for country or territory regardless of the publication language. Some ISBN registration agencies are based in national libraries or within ministries of culture, in other cases, the ISBN registration service is provided by organisations such as bibliographic data providers that are not government funded. In Canada, ISBNs are issued at no cost with the purpose of encouraging Canadian culture. In the United Kingdom, United States, and some countries, where the service is provided by non-government-funded organisations. Australia, ISBNs are issued by the library services agency Thorpe-Bowker
15.
Institute of Electrical and Electronics Engineers
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The Institute of Electrical and Electronics Engineers is a professional association with its corporate office in New York City and its operations center in Piscataway, New Jersey. It was formed in 1963 from the amalgamation of the American Institute of Electrical Engineers, today, it is the worlds largest association of technical professionals with more than 400,000 members in chapters around the world. Its objectives are the educational and technical advancement of electrical and electronic engineering, telecommunications, computer engineering, IEEE stands for the Institute of Electrical and Electronics Engineers. The association is chartered under this full legal name, IEEEs membership has long been composed of engineers and scientists. For this reason the organization no longer goes by the name, except on legal business documents. The IEEE is dedicated to advancing technological innovation and excellence and it has about 430,000 members in about 160 countries, slightly less than half of whom reside in the United States. The major interests of the AIEE were wire communications and light, the IRE concerned mostly radio engineering, and was formed from two smaller organizations, the Society of Wireless and Telegraph Engineers and the Wireless Institute. After World War II, the two became increasingly competitive, and in 1961, the leadership of both the IRE and the AIEE resolved to consolidate the two organizations. The two organizations merged as the IEEE on January 1,1963. The IEEE is incorporated under the Not-for-Profit Corporation Law of the state of New York and it was formed in 1963 by the merger of the Institute of Radio Engineers and the American Institute of Electrical Engineers. The IEEE serves as a publisher of scientific journals and organizer of conferences, workshops. IEEE develops and participates in activities such as accreditation of electrical engineering programs in institutes of higher learning. The IEEE logo is a design which illustrates the right hand grip rule embedded in Benjamin Franklins kite. IEEE has a dual complementary regional and technical structure – with organizational units based on geography and it manages a separate organizational unit which recommends policies and implements programs specifically intended to benefit the members, the profession and the public in the United States. The IEEE includes 39 technical Societies, organized around specialized technical fields, the IEEE Standards Association is in charge of the standardization activities of the IEEE. The IEEE History Center became an organization to the Engineering. The new ETHW is an effort by various engineering societies as a formal repository of topic articles, oral histories, first-hand histories, Landmarks + Milestones. The IEEE History Center is annexed to Stevens University Hoboken, NJ, in 2016, the IEEE acquired GlobalSpec, adding the provision of engineering data for a profit to its organizational portfolio
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Structured cabling
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Structured cabling is building or campus telecommunications cabling infrastructure that consists of a number of standardized smaller elements called subsystems. Structured cabling falls into six subsystems, Entrance facilities is the point where the company network ends. Equipment rooms house equipment and wiring consolidation points that serve the users inside the building or campus, backbone cabling is the inter-building and intra-building cable connections in structured cabling between entrance facilities, equipment rooms and telecommunications closets. Backbone cabling consists of the media, main and intermediate cross-connects. This system is used in data centers. A horizontal cross-connect is where the horizontal cabling connects to a panel or punch up block. Telecommunications rooms or telecommunications enclosure connects between the backbone cabling and horizontal cabling, work-area components connect end-user equipment to outlets of the horizontal cabling system. Each outlet is then patched into a switch for network use or into an IP or PBX telephone system patch panel. Structured cabling is the design and installation of a cabling systems that support multiple hardware uses systems and be suitable for today’s needs. Voice patches to PBXs in most countries require an adapter at the end to translate the configuration on 8P8C modular connectors into the local standard telephone wall socket. No adapter is needed in the U. S. as the 6P2C and 6P4C plugs most commonly used with RJ11, rJ25 and RJ61 connections are physically but not electrically compatible, and cannot be used. In the UK, an adapter must be present at the end as the 6-pin BT socket is physically incompatible with 8P8C. It is common to color code patch panel cables to identify the type of connection, cabling standards demand that all eight conductors in Cat5e/6/6A cable are connected, resisting the temptation to double-up or use one cable for both voice and data. IP phone systems, however, can run the telephone and the computer on the same wires, regardless of copper cable type the maximum distance is 90m for the permanent link installation and an allowance for 10m of patch cords at the ends combined. Cat5e and Cat6 can both effectively run PoE applications up to 90m, however, due to power dissipation there is better performance and power efficiently with Cat6A cabling running POE devices if being incorporated into a new design. Network cabling standards are used internationally and are published by ISO/IEC, CENELEC, ISO/IEC11801 heads the ISO/IEC documentation. TIA-569-B Commercial Building Standard for Telecommunications Pathways and Spaces ANSI/TIA/EIA-606-A-2002, Administration Standard for Commercial Telecommunications Infrastructure
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Copper cable certification
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These tests are done using a certification-testing tool, which provide “Pass” or “Fail” information. While certification can be performed by the owner of the network and it is this certification that allows the contractors to warranty their work. Installers who need to prove to the owner that the installation has been done correctly. Network owners who want to guarantee that the infrastructure is capable of handling a certain application will use a tester to certify the network infrastructure, in some cases, these testers are used to pinpoint specific problems. Certification tests are vital if there is a discrepancy between the installer and network owner after an installation has been performed, the performance tests and their procedures have been defined in the ANSI/TIA/EIA-568-B.1 standard and the ISO/IEC11801 standard. The TIA standard defines performance in categories and the ISO defines classes and these standards define the procedure to certify that an installation meets performance criteria in a given category or class. The standards also define that data from each test result must be collected and stored in either print or electronic format for future inspection. See TIA/EIA-568-B for wiring diagram via Mudit The Propagation Delay test tests for the time it takes for the signal to be sent from one end, the Delay Skew test tests for the difference in propagation delay between the fastest and slowest set of wire pairs. An ideal skew is between 25 and 50 nanoseconds over a 100-meter cable, the lower this skew the better, less than 25 ns is excellent, but 45 to 50 ns is marginal. The Cable Length test verifies that the cable from the transmitter to receiver does not exceed the maximum recommended distance of 100 meters in a 10BASE-T/100BASE-TX/1000BASE-T network. Insertion loss, also referred to as attenuation, refers to the loss of strength at the far end of a line compared to the signal that was introduced into the line. This loss is due to the impedance of the copper cable, the loss of energy through the cable insulation. Insertion loss is usually expressed in decibels dB with a minus sign, insertion loss increases with distance and frequency. For every 3 dB of loss, signal power is reduced by a factor of 2, return Loss is the measurement of the amount of signal that is reflected back toward the transmitter. The reflection of the signal is caused by the variations of impedance in the connectors, the greater the variation in impedance, the greater the return loss reading. If 3 pairs of wire pass by an amount, but the 4 pair barely passes. Return loss is not significant in the loss of a signal. Near-End Crosstalk is a condition that describes the occurrence of a signal from one wire pair radiating to
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