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Cross-connect
A digital cross-connect system (DCS or DXC) is a piece of circuit-switched network equipment, used in telecommunications networks, that allows lower-level TDM bit streams, such as DS0 bit streams, to be rearranged and interconnected among higher-level TDM signals, such as DS1 bit streams. DCS units are available that operate on both older T-carrier/E-carrier bit streams, as well as newer SONET/SDH bit streams. DCS devices can be used for " grooming" telecommunications traffic, switching traffic from one circuit to another in the event of a network failure, supporting automated provisioning, and other applications. Having a DCS in a circuit-switched network provides important flexibility that can otherwise only be obtained at higher cost using manual " DSX" cross-connect patch panels. It is important to realize that while DCS devices "switch" traffic, they are ''not'' packet switches—they switch ''circuits'', not packets, and the circuit arrangements they are used to man ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Cross-connect
{{unreferenced, date=February 2008 An optical cross-connect (OXC) is a device used by telecommunications carriers to switch high-speed optical signals in a fiber optic network, such as an optical mesh network. There are several ways to realize an OXC: * Opaque OXCs (electronic switching) - One can implement an OXC in the electronic domain: all the input optical signals are converted into electronic signals after they are demultiplexed by demultiplexers. The electronic signals are then switched by an electronic switch module. Finally, the switched electronic signals are converted back into optical signals by using them to modulate lasers and then the resulting optical signals are multiplexed by optical multiplexers onto outlet optical fibers. This is known as an "OEO" (Optical-Electrical-Optical) design. Cross-connects based on an OEO switching process generally have a key limitation: the electronic circuits limit the maximum bandwidth of the signal. Such an architecture preven ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traffic Grooming
Traffic grooming is the process of grouping many small telecommunications flows into larger units, which can be processed as single entities. For example, in a network using both time-division multiplexing (TDM) and wavelength-division multiplexing (WDM), two flows which are destined for a common node can be placed on the same wavelength, allowing them to be dropped by a single optical add-drop multiplexer. Often the objective of grooming is minimizing the cost of the network. The cost of line terminating equipment (LTE) (also called add/drop multiplexers or ADMs) is the most dominant component in an optical WDM network's cost. Thus grooming typically involves minimizing the usage of ADMs. This is similar to the use of virtual channels and virtual paths in ATM networks. Effective grooming requires consideration of the topology of the network and the different routes in use. This is especially useful when dealing with mesh networks. Grooming Algorithms The traffic grooming prob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T-carrier
The T-carrier is a member of the series of carrier systems developed by AT&T Bell Laboratories for digital transmission of multiplexed telephone calls. The first version, the Transmission System 1 (T1), was introduced in 1962 in the Bell System, and could transmit up to 24 telephone calls simultaneously over a single transmission line of copper wire. Subsequent specifications carried multiples of the basic T1 (1.544 Mbit/s) data rates, such as T2 (6.312 Mbit/s) with 96 channels, T3 (44.736 Mbit/s) with 672 channels, and others. Although a ''T2'' was defined as part of AT&T's T-carrier system, which defined five levels, T1 through T5, only the T1 and T3 were commonly in use.1999 ad: On the left, in an aisle seat, a man who very much "filled" his airline seat while on the right side of the aisle is a height-challenged man whose shoe toes barely reach the floor Transmission System 1 The T-carrier is a hardware specification for carrying multiple time-division mul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchronous Optical Networking
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] |
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] |
T-carrier System
The T-carrier is a member of the series of carrier systems developed by AT&T Bell Laboratories for digital transmission of multiplexed telephone calls. The first version, the Transmission System 1 (T1), was introduced in 1962 in the Bell System, and could transmit up to 24 telephone calls simultaneously over a single transmission line of copper wire. Subsequent specifications carried multiples of the basic T1 (1.544 Mbit/s) data rates, such as T2 (6.312 Mbit/s) with 96 channels, T3 (44.736 Mbit/s) with 672 channels, and others. Although a ''T2'' was defined as part of AT&T's T-carrier system, which defined five levels, T1 through T5, only the T1 and T3 were commonly in use.1999 ad: On the left, in an aisle seat, a man who very much "filled" his airline seat while on the right side of the aisle is a height-challenged man whose shoe toes barely reach the floor Transmission System 1 The T-carrier is a hardware specification for carrying multiple time-division mul ... [...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] |
Circuit Switching
Circuit switching is a method of implementing a telecommunications network in which two network nodes establish a dedicated communications channel ( circuit) through the network before the nodes may communicate. The circuit guarantees the full bandwidth of the channel and remains connected for the duration of the communication session. The circuit functions as if the nodes were physically connected as with an electrical circuit. Circuit switching originated in analog telephone networks where the network created a dedicated circuit between two telephones for the duration of a telephone call. It contrasts with message switching and packet switching used in modern digital networks in which the trunklines between switching centers carry data between many different nodes in the form of data packets without dedicated circuits. Description The defining example of a circuit-switched network is the early analog telephone network. When a call is made from one telephone to another, swit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Electric
The Western Electric Company was an American electrical engineering and manufacturing company officially founded in 1869. A wholly owned subsidiary of American Telephone & Telegraph for most of its lifespan, it served as the primary equipment manufacturer, supplier, and purchasing agent for the Bell System from 1881 to 1984 when it was dismantled. The company was responsible for many technological innovations as well as developments in industrial management. History In 1856, George Shawk, a craftsman and telegraph maker, purchased an electrical engineering business in Cleveland, Ohio. In January, 1869, Shawk had partnered with Enos M. Barton in the former Western Union repair shop of Cleveland, to manufacture burglar, fire alarms, and other electrical items. Both men were former Western Union employees. Shawk, was the Cleveland shop foreman and Barton, was a Rochester, New York telegrapher. During this Shawk and Barton partnership, one customer was an inventor sourcing parts an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Architecture
Network architecture is the design of a computer network. It is a framework for the specification of a network's physical components and their functional organization and configuration, its operational principles and procedures, as well as communication protocols used. In telecommunication, the specification of a network architecture may also include a detailed description of products and services delivered via a communications network, as well as detailed rate and billing structures under which services are compensated. The network architecture of the Internet is predominantly expressed by its use of the Internet protocol suite, rather than a specific model for interconnecting networks or nodes in the network, or the usage of specific types of hardware links. OSI model The Open Systems Interconnection model (OSI model) defines and codifies the concept of layered network architecture. Abstraction layers are used to subdivide a communications system further into smaller ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alcatel-Lucent
Alcatel–Lucent S.A. () was a French–American global telecommunications equipment company, headquartered in Boulogne-Billancourt, France. It was formed in 2006 by the merger of France-based Alcatel and U.S.-based Lucent, the latter being a successor of AT&T's Western Electric and Bell Labs. In 2014, the Alcatel-Lucent group split into two: Alcatel-Lucent Enterprise, providing enterprise communication services, and Alcatel-Lucent, selling to communications operators. The enterprise business was sold to a Chinese company in the same year, and in 2016 Nokia purchased the rest of Alcatel-Lucent. The company focused on fixed, mobile and converged networking hardware, IP technologies, software and services, with operations in more than 130 countries. It had been named Industry Group Leader for Technology Hardware & Equipment sector in the 2014 Dow Jones Sustainability Indices review and listed in the 2014 Thomson Reuters Top 100 Global Innovators for the 4th consecutive year. Al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patch Panel
A patch panel is a device or unit featuring a number of jacks, usually of the same or similar type, for the use of connecting and routing circuits for monitoring, interconnecting, and testing circuits in a convenient, flexible manner. Patch panels are commonly used in computer networking, recording studios, and radio and television. The term ''patch'' came from early use in telephony and radio studios, where extra equipment kept on standby could be temporarily substituted for failed devices. This reconnection was done via patch cords and patch panels, like the jack fields of cord-type telephone switchboards. Terminology They are also referred to as a patch bay, patch field, jack panel or jack field. Uses and connectors In recording studios, television and radio broadcast studios, and concert sound reinforcement systems, patchbays are widely used to facilitate the connection of different devices, such as microphones, electric or electronic instruments, effects (e.g. compre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
