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Category 1 Cable
Category 1 cable, also known as Cat 1, Level 1, or voice-grade copper, is a grade of unshielded twisted pair cabling designed for telephone communications, and at one time was the most common on-premises wiring. The maximum frequency suitable for transmission over Cat 1 cable is 1 MHz, but Cat 1 is not currently considered adequate for data transmission (though it was at one time used for that purpose on the Apple Macintosh starting in the late 1980s in the form of Farallon Computing's//NetTopia's PhoneNet, an implementation of Apple's LocalTalk networking hardware standard). Although not an official category standard established by TIA/EIA, Category 1 has become the de facto name given to Level 1 cables originally defined by Anixter International, the distributor. Cat 1 cable was typically used for networks that carry only voice traffic, for example telephones. Official TIA/EIA-568 ANSI/TIA-568 is a technical standard for commercial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unshielded Twisted Pair
Twisted pair cabling is a type of wiring used for communications in which two conductors of a single circuit are twisted together for the purposes of improving electromagnetic compatibility. Compared to a single conductor or an untwisted balanced pair, a twisted pair reduces electromagnetic radiation from the pair and crosstalk between neighboring pairs and improves rejection of external electromagnetic interference. It was invented by Alexander Graham Bell. For additional noise immunity, twisted-pair cabling may be shielded. Cable with shielding is known as shielded twisted pair (STP) and without as unshielded twisted pair (UTP). Explanation A twisted pair can be used as a balanced line, which as part of a balanced circuit can greatly reduce the effect of noise currents induced on the line by coupling of electric or magnetic fields. The idea is that the currents induced in each of the two wires are very nearly equal. The twisting ensures that the two wires are on average ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone
A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into electronic signals that are transmitted via cables and other communication channels to another telephone which reproduces the sound to the receiving user. The term is derived from el, τῆλε (''tēle'', ''far'') and φωνή (''phōnē'', ''voice''), together meaning ''distant voice''. A common short form of the term is ''phone'', which came into use early in the telephone's history. In 1876, Alexander Graham Bell was the first to be granted a United States patent for a device that produced clearly intelligible replication of the human voice at a second device. This instrument was further developed by many others, and became rapidly indispensable in business, government, and in households. The essential elements of a telephone are a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
On-premises Wiring
On-premises wiring (customer premises wiring) is customer-owned telecommunication transmission or distribution lines. The transmission lines may be metallic (copper) or optical fiber, and may be installed within or between buildings. Premises wiring may consist of horizontal wiring, vertical wiring, and backbone cabling. It may extend from the point-of-entry to user work areas. Any type of telecommunications or data wiring is considered premises wiring, including telephone, computer/data, intercom, closed-circuit television. Premises networks are wired worldwide, across every industry, in both small and large-scale applications. Any type or number of topologies may be used – star, bus, ring, etc. In 1989, the United States Federal Communications Commission (FCC) deregulated charges for maintaining at home ''inside wiring''; the corresponding monthly charge was dropped January 1990. Ownership The ownership of on-premises wiring varies between jurisdictions: It depends on t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
McGraw Hill
McGraw Hill is an American educational publishing company and one of the "big three" educational publishers that publishes educational content, software, and services for pre-K through postgraduate education. The company also publishes reference and trade publications for the medical, business, and engineering professions. McGraw Hill operates in 28 countries, has about 4,000 employees globally, and offers products and services to about 140 countries in about 60 languages. Formerly a division of The McGraw Hill Companies (later renamed McGraw Hill Financial, now S&P Global), McGraw Hill Education was divested and acquired by Apollo Global Management in March 2013 for $2.4 billion in cash. McGraw Hill was sold in 2021 to Platinum Equity for $4.5 billion. Corporate History McGraw Hill was founded in 1888 when James H. McGraw, co-founder of the company, purchased the ''American Journal of Railway Appliances''. He continued to add further publications, eventually establishing The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apple Macintosh
The Mac (known as Macintosh until 1999) is a family of personal computers designed and marketed by Apple Inc. Macs are known for their ease of use and minimalist designs, and are popular among students, creative professionals, and software engineers. The current lineup includes the MacBook Air and MacBook Pro laptops, as well as the iMac, Mac Mini, Mac Studio and Mac Pro desktops. Macs run the macOS operating system. The first Mac was released in 1984, and was advertised with the highly-acclaimed "1984" ad. After a period of initial success, the Mac languished in the 1990s, until co-founder Steve Jobs returned to Apple in 1997. Jobs oversaw the release of many successful products, unveiled the modern Mac OS X, completed the 2005-06 Intel transition, and brought features from the iPhone back to the Mac. During Tim Cook's tenure as CEO, the Mac underwent a period of neglect, but was later reinvigorated with the introduction of popular high-end Macs and the ongoing Apple s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Farallon Computing
Farallon, later renamed Netopia, was a computer networking company headquartered in Berkeley, and subsequently Emeryville, California, that produced a wide variety of products including bridges, repeaters and switches, and in their later Netopia incarnation, modems, routers, gateways, and Wi-Fi devices. The company also produced the NBBS (Netopia Broadband Server Software) and, as Farallon, Timbuktu remote administration software, as well as the MacRecorder, the first audio capture and manipulation products for the Macintosh (later sold to Macromedia). The company was founded in 1986 and changed its name to Netopia in 1998. Farallon originated several notable technologies, including: * PhoneNet, an implementation of AppleTalk over plain ("Cat-3") telephone wiring or, more commonly, EIA-TIA 568A/B structured cabling systems. Many versions of the product were produced, but the original product was a commercialized version of a kit developed and produced by BMUG, the Berkeley Macin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anixter International
Anixter International Inc. is a company based in Glenview, Illinois, United States and founded in 1957. The company supplies goods and services for communications, security, networking, audio-visual, and industrial control applications. The company operates with three major divisions: Network & Security Solutions, Electrical and Electronic Solutions, and Utility Power Solutions. Aerospace Hardware, once considered the fourth division, was sold by Anixter in 2011 to Greenbriar Equity, which formed Align Aerospace. In 2002 Anixter was named as a Forbes "Platinum 400" company. On January 13, 2020, Anixter agreed to be acquired by WESCO International for $4.5 billion in cash and WESCO stock. Anixter's shares ceased trading as of June 22, 2020. Early history Anixter was started in 1956 by brothers Alan and Bill Anixter. Known originally as Anixter Brothers, the two opened Anixter as a wholesale distribution company that resold cable. The two brothers received a $20,000 loan from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TIA/EIA-568
ANSI/TIA-568 is a technical standard for commercial building cabling for telecommunications products and services. The title of the standard is ''Commercial Building Telecommunications Cabling Standard'' and is published by the Telecommunications Industry Association (TIA), a body accredited by the American National Standards Institute (ANSI). , the revision status of the standard is ''ANSI/TIA-568-D'', published 2015, which replaced TIA/EIA-568-C of 2009, revision B of 2001, and revision A of 1995, and the initial issue of 1991, which are now obsolete. Perhaps the best-known features of ANSI/TIA-568 are the pin and pair assignments for eight-conductor 100-ohm balanced twisted pair cabling. These assignments are named ''T568A'' and ''T568B''. History 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 Electronic Industries Alliance (EIA), to define standar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Category 3 Cable
Category 3 cable, commonly known as or station wire, and less commonly known as VG or voice-grade (as, for example, in 100BaseVG), is an unshielded twisted pair (UTP) cable used in telephone wiring. It is part of a family of standards defined jointly by the Electronic Industries Alliance (EIA) and the Telecommunications Industry Association (TIA) and published in TIA/EIA-568-B. Although designed to reliably carry data up to 10 Mbit/s, modern data networks run at much higher speeds, and or better cable is generally used for new installations. Networking was widely used in computer networking in the early 1990s for 10BASE-T Ethernet and, to a much lesser extent, for 100BaseVG Ethernet, Token Ring and 100BASE-T4. The original Power over Ethernet 802.3af specification supports the use of cable, but the later 802.3at Type 2 high-power variation does not.IEEE 802.3at-2009, clause 33.1.1c In some use cases and for short distances, Cat 3 may be capable of carrying 100BASE- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signal Cables
A shielded cable or screened cable is an electrical cable that has a common conductive layer around its conductors for electromagnetic shielding. This shield is usually covered by an outermost layer of the cable. Common types of cable shielding can most broadly be categorized as foil type (hereunder: metallised film Metallised films (or metallized films) are polymer films coated with a thin layer of metal, usually aluminium. They offer the glossy metallic appearance of an aluminium foil at a reduced weight and cost. Metallised films are widely used for decorati ...), contraspiralling wire strands (braided or unbraided) or both. A longitudinal wire may be necessary with dielectric spiral foils to short out each turn. The shield acts as a Faraday cage – a surface that reflects electromagnetic radiation. This reduces both the Electromagnetic interference, interference from outside noise onto the signals and the signals from radiating out and potentially disturbing other devices ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
