1A2 Key Telephone System
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1A2 Key Telephone System
The 1A2 Key Telephone System is a business telephone system developed and distributed by the Western Electric Company for the Bell System. The 1A2 Key Telephone System is a modular system that provided flexible solutions for a variety of telephone service requirements. It provides multiple users with control over multiple telephone lines without the requirement for an operator, system attendant, or receptionist. Each user can select a specific telephone line to place calls on, or to answer calls, and manage those calls by placing them on hold or transferring them to other stations. The system provides options for station-to-station signaling and intercom, and music-on-hold. The control functions are operated directly on each telephone instrument with a set of push buttons (''keys'') that have lamps installed internally to provide visual indication of line status. Introduced in 1964, the 1A2 system represents a stage of key telephone systems development at Bell Laboratories that s ...
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25 Pair Color Code Chart
5 (five) is a number, numeral and digit. It is the natural number, and cardinal number, following 4 and preceding 6, and is a prime number. It has attained significance throughout history in part because typical humans have five digits on each hand. In mathematics 5 is the third smallest prime number, and the second super-prime. It is the first safe prime, the first good prime, the first balanced prime, and the first of three known Wilson primes. Five is the second Fermat prime and the third Mersenne prime exponent, as well as the third Catalan number, and the third Sophie Germain prime. Notably, 5 is equal to the sum of the ''only'' consecutive primes, 2 + 3, and is the only number that is part of more than one pair of twin primes, ( 3, 5) and (5, 7). It is also a sexy prime with the fifth prime number and first prime repunit, 11. Five is the third factorial prime, an alternating factorial, and an Eisenstein prime with no imaginary part and real part of the form 3 ...
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RJ21
A registered jack (RJ) is a standardized telecommunication network interface for connecting voice and data equipment to a service provided by a local exchange carrier or long distance carrier. Registration interfaces were first defined in the ''Universal Service Ordering Code'' (USOC) system of the Bell System in the United States for complying with the registration program for customer-supplied telephone equipment mandated by the Federal Communications Commission (FCC) in the 1970s. They were subsequently codified in title 47 of the Code of Federal Regulations Part 68. Registered jack connections began to see use after their invention in 1973 by Bell Labs. The specification includes physical construction, wiring, and signal semantics. Accordingly, registered jacks are primarily named by the letters ''RJ'', followed by two digits that express the type. Additional letter suffixes indicate minor variations. For example, RJ11, RJ14, and RJ25 are the most commonly used interfaces f ...
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Wink Pulsing
Winking is a telephony signaling technique used both in connection with DC signaling on a trunk, and with indicator lamps on a key telephone. In telephone switching systems, wink pulsing is recurring pulsing in which the off-condition is relatively short compared to the on-condition. In wink start trunks, the exchange at the originating end sends an off-hook to alert to a call. The terminating end indicates readiness to receive the dialed telephone number by sending an off-hook of approximately half a second duration, or "wink". Upon receiving this go ahead signal, the originating end uses multi-frequency or other address signalling to send the phone number. On 1A2 key systems or similar key-operated telephone instruments, the hold position, ''i.e.,'' the hold condition, of a line is often indicated by winking the associated lamp at 120 impulses per minute. During 6% of the pulse period In medicine, a pulse represents the tactile arterial palpation of the cardiac cycle (he ...
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Backplane
A backplane (or "backplane system") is a group of electrical connectors in parallel with each other, so that each pin of each connector is linked to the same relative pin of all the other connectors, forming a computer bus. It is used as a backbone to connect several printed circuit boards together to make up a complete computer system. Backplanes commonly use a printed circuit board, but wire-wrapped backplanes have also been used in minicomputers and high-reliability applications. A backplane is generally differentiated from a motherboard by the lack of on-board processing and storage elements. A backplane uses plug-in cards for storage and processing. Usage Early microcomputer systems like the Altair 8800 used a backplane for the processor and expansion cards. Backplanes are normally used in preference to cables because of their greater reliability. In a cabled system, the cables need to be flexed every time that a card is added or removed from the system; this flexing even ...
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Music On Hold
Music on hold (MOH) is the business practice of playing recorded music to fill the silence that would be heard by telephone callers who have been placed on hold. It is especially common in situations involving customer service. Music on hold is sometimes referred to as phone on hold, message on hold, on hold messaging, or hold music. Development Music on hold was created by Alfred Levy, an inventor, factory owner, and entrepreneur. In 1962, Levy discovered a problem with the phone lines at his factory: a loose wire was touching a metal girder on the building. This made the building a giant receiver, so that the audio broadcast signal from a radio station next door would transmit through the loose wire, and could be heard when calls were put on hold. Levy patented his work in 1966. While other advancements have come to change and enhance the technology, it was this initial patent creation that began the evolution for today's music on hold. Equipment and formats Most MOH systems ...
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Punch Block
A punch-down block (also punchdown block, punch block, punchblock, quick-connect block and other variations) is a type of electrical connection often used in telephony. It is named because the solid copper wires are "punched down" into short open-ended slots which are a type of insulation-displacement connector. These slots, usually cut crosswise (not lengthwise) across an insulating plastic bar, contain two sharp metal blades which cut through the wire's insulation as it is punched down. These blades hold the wire in position and make the electrical contact with the wire as well. Overview A tool called a punch down tool is used to push the wire down firmly and properly into the slot. Some will automatically cut any excess wire off. The exact size and shape of the tool blade varies by manufacturer, which can cause problems for those working on existing installations, especially when there is a poorly documented mix of different brands. Punch-down blocks are a very quick and e ...
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66 Block
66 may refer to: * 66 (number) * One of the years 66 BC, AD 66, 1966, 2066 * "66" (song), a song by Lil Yachty featuring Trippie Redd *66, a song by The Afghan Whigs, from the album 1965 *Sixty-Six (card game), a German card game * ''Sixty Six'' (film), a 2006 film *''Sixty-Six'', a novel by film director Barry Levinson See also *Order 66 (other) *Phillips 66, an American multinational energy company *U.S. Route 66, a historic U.S. highway *WNBC (AM) WFAN (660 AM) is a commercial radio station licensed to New York, New York, carrying a sports radio format known as "Sports Radio 66 AM and 101.9 FM" or "The Fan". Owned by Audacy, Inc., the station serves the New York metropolitan area while ...
, on frequency 660 AM, was commonly referred historically as "66 WNBC" {{numberdis ...
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Micro Ribbon
The micro ribbon or miniature ribbon connector is a common type of electrical connector for a variety of applications, such as in computer and telecommunications equipment having many contacts. The connector contains two parallel rows of contacts within a shielded case having a characteristic D-shape similar to that used in D-subminiature connectors. The contacts are not pins, but small flat bands of metal, called ribbon contacts. The connectors are manufactured in many capacities, including 14-, 24-, 36-, 50-, 64-, and 100- pin varieties. They may be mounted on boards, panels, or may terminate cables. Wires are attached by means of solder, crimping or insulation displacement. Female connectors have bail locks for a sturdy connection to the male connector. Screws may also be employed to secure connections. This connector type is also known as ''telco'', ''25-pair'', ''miniature delta ribbon'', ''mini D ribbon'', ''delta ribbon'', ''MDR'', ''Amphenol'', or ''CHAMP'' min ...
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Amphenol
Amphenol Corporation is a major producer of electronic and fiber optic connectors, cable and interconnect systems such as coaxial cables. Amphenol is a portmanteau from the corporation's original name, American Phenolic Corp. History Amphenol was founded in Chicago in 1932 by entrepreneur Arthur J. Schmitt, whose first product was a tube socket for radio tubes (valveholder bases). Amphenol expanded significantly during World War II, when the company became the primary manufacturer of connectors used in military hardware, including airplanes and radios. From 1967 to 1982 it was part of Bunker Ramo Corporation. The company sells its products into diverse electronics markets, including military-aerospace, industrial, automotive, information technology, mobile phones, wireless infrastructure, broadband, medical, and pro audio. Operations are located in more than 60 locations around the world. Amphenol's world headquarters is located in Wallingford, Connecticut. The largest di ...
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25-pair Color Code
The 25-pair color code, originally known as even-count color code, is a color code used to identify individual conductors in twisted-pair wiring for telecommunications. Color coding With the development of new generations of telecommunication cables with polyethylene-insulated conductors (''PIC'') by Bell Laboratories for the Bell System in the 1950s, new methods were developed to mark each individual conductor in cables. Each wire is identified by the combination of two colors, one of which is the major color, and the second the minor color. Major and minor colors are chosen from two different groups of five, resulting in 25 color combinations. The color combinations are applied to the insulation that covers each conductor. Typically, one color is a prominent background color of the insulation, and the other is a tracer, consisting of stripes, rings, or dots, applied over the background. The background color always matches the tracer color of its paired conductor, and vice versa ...
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Tip And Ring
Tip and ring are the two conductors or sides of a telephone line. Their names are derived from the telephone plugs used for connecting telephone calls in manual switchboards. One side of the line is connected to the metal ''tip'' of the plug, and the second is connected to a metal ''ring'' behind the tip, separated and insulated from the tip by a non-conducting material. When inserted into a jack, the plug's tip conductor connects first, followed by the ring conductor. In many European countries, tip and ring are referred to as the ''A'' and ''B'' wires. Neither of the tip and ring conductors is permanently connected to earth ground, but may be connected to ground during signaling operations. Typically, the ring conductor has a direct current (DC) potential of to with respect to the tip conductor when the line is in the on-hook (idle) state. Floating both conductors, not referencing either one to ground, minimizes the pickup of hum from any nearby alternating current (AC) power ...
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