Networking cables are used to connect one network device to other network devices or to connect two or more computers to share printer, scanner etc. Different types of network cables like Coaxial cable, Optical fiber cable, Twisted Pair cables are used depending on the network's topology, protocol and size. The devices can be separated by a few meters (e.g. via Ethernet) or nearly unlimited distances (e.g. via the interconnections of the Internet).
While wireless networks are much easier deployed when total throughput is not an issue, most permanent larger computer networks use cables to transfer signals from one point to another.
Twisted pair cabling is a form of wiring in which pairs of wires (the forward and return conductors of a single circuit) are twisted together for the purposes of canceling outelectromagnetic interference (EMI) from other wire pairs and from external sources. This type of cable is used for home and corporate Ethernet networks.
There are two major types of twisted pair cables: shielded, unshielded.
Ethernet crossover cable
An Ethernet crossover cable is a type of twisted pair Ethernet cable used to connect computing devices together directly that would normally be connected via a network switch,hub or router, such as directly connecting two personal computers via their network adapters. Most current Ethernet devices support Auto MDI-X, so it doesn't matter whether you use crossover or straight cables.
An optical fiber cable consists of a center glass core surrounded by several layers of protective material. The outer insulating jacket is made of Teflon or PVC to prevent interference. Optical fiber deployment is more expensive than copper but offers higher bandwidth and can cover longer distances.
There are two major types of optical fiber cables: short-range multi-mode fiber and long-range single-mode fiber.
Coaxial lines confine the electromagnetic wave inside the cable, between the center conductor and the shield. The transmission of energy in the line occurs totally through the dielectric inside the cable between the conductors. Coaxial lines can therefore be bent and twisted (subject to limits) without negative effects, and they can be strapped to conductive supports without inducing unwanted currents in them.
The most common use for coaxial cables is for television and other signals with a bandwidth of several hundred megahertz to gigahertz. Although in most homes coaxial cables have been installed for transmission of TV signals, new technologies (such as the ITU-T G.hn standard) open the possibility of using home coaxial cable for high-speed home networking applications (Ethernet over coax).
In the 20th century they carried long distance telephone connections.
A patch cable is an electrical or optical cable used to connect one electronic or optical device to another for signal routing. Devices of different types (e.g. a switch connected to a computer, or a switch connected to a router) are connected with patch cords. Patch cords are usually produced in many different colors so as to be easily distinguishable,and are relatively short, perhaps no longer than two meters. In contrast to on-premises wiring, patch cables are more flexible but may also be less durable.
Although power wires are not designed for networking applications, new technologies like Power line communication allows these wires to also be used to interconnect home computers, peripherals or other networked consumer products. On December 2008, the ITU-T adopted Recommendation G.hn/G.9960 as the first worldwide standard for high-speed powerline communications.
Ethernet was developed at Xerox PARC between 1973 and 1974.It was inspired by ALOHAnet, which Robert Metcalfe had studied as part of his PhD dissertation.The idea was first documented in a memo that Metcalfe wrote on May 22, 1973, where he named it after the disproven luminiferous ether as an "omnipresent, completely-passive medium for the propagation of electromagnetic waves". In 1975, Xerox filed a patent application listing Metcalfe, David Boggs, Chuck Thacker, and Butler Lampson as inventors.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. He convinced Digital Equipment Corporation (DEC), 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 a global 16-bit Ethertype-type field. 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 same time and resulted in the publication of IEEE 802.3 on June 23, 1983.
Ethernet initially competed with two largely proprietary systems, Token Ring and Token Bus. Because Ethernet was able to adapt to market realities and shift to inexpensive and ubiquitous twisted pair wiring, these proprietary protocols soon found themselves competing in a market inundated by Ethernet products, and, by the end of the 1980s, Ethernet was clearly the dominant network technology. In the process, 3Com became a major company. 3Com shipped its first 10 Mbit/s Ethernet 3C100 NIC in March 1981, and that year started selling adapters for PDP-11s and VAXes, as well as Multibus-based Intel and Sun Microsystems computers. This was followed quickly by DEC's Unibus to Ethernet adapter, which DEC sold and used internally to build its own corporate network, which reached over 10,000 nodes by 1986, making it one of the largest computer networks in the world at that time. An Ethernet adapter card for the IBM PC was released in 1982, and, by 1985, 3Com had sold 100,000.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 greatly sped up with the introduction of 10BASE-T and its relatively small modular connector, at which point Ethernet ports appeared even on low-end motherboards.
Since then, Ethernet technology has evolved to meet new bandwidth and market requirements.In addition to computers, Ethernet is now used to interconnect appliances and other personal devices.It is used in industrial applications and is quickly replacing legacy data transmission systems in the world's telecommunications networks. By 2010, the market for Ethernet equipment amounted to over $16 billion per year.
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