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5ESS Switching System
The 5ESS Switching System is a Class 5 telephone electronic switching system developed by Western Electric for the American Telephone and Telegraph Company (AT&T) and the Bell System in the United States. It came into service in 1982 and the last unit was produced in 2003. History The 5ESS came to market as the Western Electric No. 5 ESS. It commenced service in Seneca, Illinois on 25 March 1982, and was destined to replace the Number One Electronic Switching System (1ESS and 1AESS) and other electromechanical systems in the 1980s and 1990s. The 5ESS was also used as a Class-4 telephone switch or as a hybrid Class 4/Class 5 switch in markets too small for the 4ESS. Approximately half of all US central offices are served by 5ESS switches. The 5ESS is also exported internationally, and manufactured outside the US under license. The 5ESS–2000 version, introduced in the 1990s, increased the capacity of the switching module (SM), with more peripheral modules and more optical link ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lucent 5ESS GSM Mobile Switching Centre
Lucent Technologies, Inc. was an American multinational telecommunications equipment company headquartered in Murray Hill, New Jersey. It was established on September 30, 1996, through the divestiture of the former AT&T Technologies business unit of AT&T Corporation, which included Western Electric and Bell Labs. Lucent was merged with Alcatel SA of France on December 1, 2006, forming Alcatel-Lucent. Alcatel-Lucent was absorbed by Nokia in January 2016. Name Lucent means "light-bearing" in Latin. The name was applied for in 1996 at the time of the split from AT&T. The name was widely criticised, as the logo was to be, both internally and externally. Corporate communications and business cards included the strapline 'Bell Labs Innovations' in a bid to retain the prestige of the internationally famous research lab, within a new business under an as-yet unknown name. This same linguistic root also gives Lucifer, "the light bearer" (from lux, 'light', and ferre, 'to bear'), w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Memory
In computing, memory is a device or system that is used to store information for immediate use in a computer or related computer hardware and digital electronic devices. The term ''memory'' is often synonymous with the term ''primary storage'' or '' main memory''. An archaic synonym for memory is store. Computer memory operates at a high speed compared to storage that is slower but less expensive and higher in capacity. Besides storing opened programs, computer memory serves as disk cache and write buffer to improve both reading and writing performance. Operating systems borrow RAM capacity for caching so long as not needed by running software. If needed, contents of the computer memory can be transferred to storage; a common way of doing this is through a memory management technique called ''virtual memory''. Modern memory is implemented as semiconductor memory, where data is stored within memory cells built from MOS transistors and other components on an integrated c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Line Card
A line card or digital line card is a modular electronic circuit designed to fit on a separate printed circuit board (PCB) and interface with a telecommunications access network. A line card typically interfaces the twisted pair cable of a plain old telephone service (POTS) local loop to the public switched telephone network (PSTN). Telephone line cards perform multiple tasks, such as analog-to-digital and digital-to-analog conversion of voice, off-hook detection, ring supervision, line integrity tests, and other BORSCHT functions. In some telephone exchange designs, the line cards generate ringing current and decode DTMF signals. The line card in a subscriber loop carrier is called a subscriber line interface card (SLIC). A line card can terminate a line supporting voice POTS service, ISDN service, DSL service, or proprietary ones. Some line cards are capable of terminating more than one type of service. Since an access network element is usually intended to interface many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DMS-100
The DMS-100 is a member of the Digital Multiplex System (DMS) product line of telephone exchange switches manufactured by Northern Telecom. Designed during the 1970s and released in 1979, it can control 100,000 telephone lines. The purpose of the DMS-100 Switch is to provide local service and connections to the PSTN public telephone network. It is designed to deliver services over subscribers' telephone lines and trunks. It provides plain old telephone service (POTS), mobility management for cellular phone systems, sophisticated business services such as automatic call distribution (ACD), Integrated Services Digital Network (ISDN), and Meridian Digital Centrex (MDC), formerly called Integrated Business Network (IBN). It also provides Intelligent Network functions (AIN, CS1-R, ETSI INAP). It is used in countries throughout the world. There are also DMS-200 and DMS-250 variants for tandem switches. Much of the hardware used in the DMS-100, with the possible exception of the line ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nortel
Nortel Networks Corporation (Nortel), formerly Northern Telecom Limited, was a Canadian multinational telecommunications and data networking equipment manufacturer headquartered in Ottawa, Ontario, Canada. It was founded in Montreal, Quebec, in 1895 as the Northern Electric and Manufacturing Company. Until an antitrust settlement in 1949, Northern Electric was owned principally by Bell Canada and the Western Electric Company of the Bell System, producing large volumes of telecommunication equipment based on licensed Western Electric designs. At its height, Nortel accounted for more than a third of the total valuation of all companies listed on the Toronto Stock Exchange (TSX), employing 94,500 people worldwide. In 2009, Nortel filed for bankruptcy protection in Canada and the United States, triggering a 79% decline of its corporate stock price. The bankruptcy case was the largest in Canadian history and left pensioners, shareholders and former employees with enormous losses. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time Slot Interchange
{{Short description, Network switch storing data in RAM in one sequence A time-slot interchange (TSI) switch is a network switch that stores data in RAM in one sequence, and reads it out in a different sequence. It uses RAM, a small routing memory and a counter. Like any switch, it has input and output ports. The RAM stores the packets or other data that arrive via its input terminal. Mechanism In a pure time-slot interchange switch, there is only one physical input, and one physical output. Each physical connection is an opportunity for a switching fabric to fail. The limited number of connections of this switch is therefore valuable in a large switching fabric, because it makes this type of switching very reliable. The disadvantage of this type of switch is that it introduces delay into the signals. When a packet (or byte, on telephone switches) comes to the input, the switch stores the data in RAM in one sequence, and reads it out in a different sequence. Switch designs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distributed Switching
Distribution may refer to: Mathematics *Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations * Probability distribution, the probability of a particular value or value range of a variable **Cumulative distribution function, in which the probability of being no greater than a particular value is a function of that value *Frequency distribution, a list of the values recorded in a sample *Inner distribution, and outer distribution, in coding theory *Distribution (differential geometry), a subset of the tangent bundle of a manifold *Distributed parameter system, systems that have an infinite-dimensional state-space *Distribution of terms, a situation in which all members of a category are accounted for *Distributivity, a property of binary operations that generalises the distributive law from elementary algebra * Distribution (number theory) *Distribution problems, a common type of problems in combinatorics where the goal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multi-mode Optical Fiber
Multi-mode optical fiber is a type of optical fiber mostly used for communication over short distances, such as within a building or on a campus. Multi-mode links can be used for data rates up to 100 Gbit/s. Multi-mode fiber has a fairly large core diameter that enables multiple light modes to be propagated and limits the maximum length of a transmission link because of modal dispersion. The standard G.651.1 defines the most widely used forms of multi-mode optical fiber. Applications The equipment used for communications over multi-mode optical fiber is less expensive than that for single-mode optical fiber. Typical transmission speed and distance limits are 100 Mbit/s for distances up to 2 km (100BASE-FX), 1 Gbit/s up to 1000 m, and 10 Gbit/s up to 550 m. Because of its high capacity and reliability, multi-mode optical fiber generally is used for backbone applications in buildings. An increasing number of users are taking the benefits of fiber closer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Signal 1
Digital Signal 1 (DS1, sometimes DS-1) is a T-carrier signaling scheme devised by Bell Labs. DS1 is the primary digital telephone standard used in the United States, Canada and Japan and is able to transmit up to 24 multiplexed voice and data calls over telephone lines. E-carrier is used in place of T-carrier outside the United States, Canada, Japan, and South Korea. DS1 is the logical bit pattern used over a physical T1 line; in practice, the terms ''DS1'' and ''T1'' are often used interchangeably. Overview T1 refers to the primary digital telephone carrier system used in North America. T1 is one line type of the PCM T-carrier hierarchy. T1 describes the cabling, signal type, and signal regeneration requirements of the carrier system. The signal transmitted on a T1 line, referred to as the DS1 signal, consists of serial bits transmitted at the rate of 1.544 Mbit/s. The type of line code used is called Alternate Mark Inversion (AMI). Digital Signal Designation is the classifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SONET
Synchronous optical networking (SONET) and synchronous digital hierarchy (SDH) are standardized protocols that transfer multiple digital bit streams synchronously over optical fiber using lasers or highly coherent light from light-emitting diodes (LEDs). At low transmission rates data can also be transferred via an electrical interface. The method was developed to replace the plesiochronous digital hierarchy (PDH) system for transporting large amounts of telephone calls and data traffic over the same fiber without the problems of synchronization. SONET and SDH, which are essentially the same, were originally designed to transport circuit mode communications (e.g., DS1, DS3) from a variety of different sources, but they were primarily designed to support real-time, uncompressed, circuit-switched voice encoded in PCM format. The primary difficulty in doing this prior to SONET/SDH was that the synchronization sources of these various circuits were different. This meant that each ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Signal 3
A Digital Signal 3 (DS3) is a digital signal level 3 T-carrier. It may also be referred to as a T3 line. *The data rate for this type of signal is 44.736 Mbit/s (45 Mb). *DS3 uses 75ohm coaxial cable and BNC connectors. *This level of carrier can transport 28 DS1 level signals within its payload. *This level of carrier can transport 672 DS0 level channels within its payload. *Such circuits are the usual kind between telephony carriers, both wired and wireless, and typically by OC1 optical connections. Cabling DS3 interconnect cables must be made with true 75-ohm coaxial cable and connectors. Cables or connectors which are 50 ohms or which significantly deviate from 75 ohms will result in signal reflections which will lower the performance of the connection, possibly to the point of not working. GR-139-CORE ''Generic Requirements for Central Office Coaxial Cable'', defines type 734 and 735 cables for this application. Due to losses, there are differing distance limitations for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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