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Network Termination 1
Network Termination 1 (NT1) or Network Termination type 1 refers to equipment in an Integrated Services Digital Network (ISDN) that physically and electrically terminates the network at the customer's premises. The NT1 network termination provides signal conversion and timing functions which correspond to layer 1 of the OSI model. In a Basic Rate Interface, the NT1 connects to line termination (LT) equipment in the provider's telephone exchange via the local loop two wire U interface and to customer equipment via the four wire S interface or T interface. The S and T interfaces are electrically equivalent, and the customer equipment port of a NT1 is often labelled as S/T interface. There are many types of NT1 available. In the United States, the NT1 is considered customer-premises equipment In telecommunications, a customer-premises equipment or customer-provided equipment (CPE) is any terminal and associated equipment located at a subscriber's premises and connected with a c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ISDN
Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Work on the standard began in 1980 at Bell Labs and was formally standardized in 1988 in the CCITT "Red Book". By the time the standard was released, newer networking systems with much greater speeds were available, and ISDN saw relatively little uptake in the wider market. One estimate suggests ISDN use peaked at a worldwide total of 25 million subscribers at a time when 1.3 billion analog lines were in use. ISDN has largely been replaced with digital subscriber line (DSL) systems of much higher performance. Prior to ISDN, the telephone system consisted of digital links like T1/ E1 on the long-distance lines between telephone company offices and analog signals on copper telephone wires to the customers, the " last mile". At the time, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Termination
A network termination (NT) (also NTE for network termination equipment) is a device that connects the customer's data or telephone equipment to a carrier's line that comes into a building or an office. The NT device provides a connection for terminal equipment (TE) and terminal adapter (TA) equipment to the local loop. The network termination used in the specific case of an ISDN Basic Rate Interface is called an NT1. See also * Demarcation point * Network interface device upTwo simple NIDs, carrying six lines each, on the outside of a building upA German copper phone line termination box called '' Abschlusspunkt LinienTechnik'' (APL, " Demarcation point") In telecommunications, a network interface device (NID; ... * User–network interface Telecommunications equipment Local loop {{Telecomm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Layer 1
In the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first and lowest layer; The layer most closely associated with the physical connection between devices. This layer may be implemented by a PHY chip. The physical layer provides an electrical, mechanical, and procedural interface to the transmission medium. The shapes and properties of the electrical connectors, the frequencies to broadcast on, the line code to use and similar low-level parameters, are specified by the physical layer. Role The physical layer defines the means of transmitting a stream of raw bits over a physical data link connecting network nodes. The bitstream may be grouped into code words or symbols and converted to a physical signal that is transmitted over a transmission medium. The physical layer consists of the electronic circuit transmission technologies of a network. It is a fundamental layer underlying the higher level functions in a network, and can be impleme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OSI Model
The Open Systems Interconnection model (OSI model) is a conceptual model that 'provides a common basis for the coordination of SOstandards development for the purpose of systems interconnection'. In the OSI reference model, the communications between a computing system are split into seven different abstraction layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application. The model partitions the flow of data in a communication system into seven abstraction layers to describe networked communication from the physical implementation of transmitting bits across a communications medium to the highest-level representation of data of a distributed application. Each intermediate layer serves a class of functionality to the layer above it and is served by the layer below it. Classes of functionality are realized in all software development through all and any standardized communication protocols. Each layer in the OSI model has its own well-defined functi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basic Rate Interface
Basic Rate Interface (BRI, 2B+D, 2B1D) or Basic Rate Access is an Integrated Services Digital Network (ISDN) configuration intended primarily for use in subscriber lines similar to those that have long been used for voice-grade telephone service. As such, an ISDN BRI connection can use the existing telephone infrastructure at a business. The BRI configuration provides 2 data (bearer) channels (B channels) at 64 kbit/s each and 1 control (delta) channel (D channel) at 16 kbit/s. The B channels are used for voice or user data, and the D channel is used for any combination of data, control/signaling, and X.25 packet networking. The 2 B channels can be aggregated by channel bonding providing a total data rate of 128 kbit/s. The BRI ISDN service is commonly installed for residential or small business service (ISDN PABX) in many countries. In contrast to the BRI, the Primary Rate Interface (PRI) configuration provides more B channels and operates at a higher bit rate. Physical i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone Exchange
A telephone exchange, telephone switch, or central office is a telecommunications system used in the public switched telephone network (PSTN) or in large enterprises. It interconnects telephone subscriber lines or virtual circuits of digital systems to establish telephone calls between subscribers. In historical perspective, telecommunication terms have been used with different semantics over time. The term ''telephone exchange'' is often used synonymously with ''central office'', a Bell System term. Often, a ''central office'' is defined as a building used to house the inside plant equipment of potentially several telephone exchanges, each serving a certain geographical area. Such an area has also been referred to as the exchange or exchange area. In North America, a central office location may also be identified as a ''wire center'', designating a facility to which a telephone is connected and obtains dial tone. For business and billing purposes, telecommunication carriers defi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Local Loop
In telephony, the local loop (also referred to as the local tail, subscriber line, or in the aggregate as the last mile) is the physical link or circuit that connects from the demarcation point of the customer premises to the edge of the common carrier or telecommunications service provider's network. At the edge of the carrier access network in a traditional public telephone network, the local loop terminates in a circuit switch housed in an incumbent local exchange carrier or telephone exchange. Infrastructure Traditionally, the local loop was an electrical circuit in the form of a single pair of conductors from the telephone on the customer's premises to the local telephone exchange. Single-wire earth return lines had been used in some countries until the introduction of electric tramways from the 1900s made them unusable. Historically the first section was often an aerial open-wire line, with several conductors attached to porcelain insulators on cross-arms on "telegra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
U Interface
U or u, is the twenty-first and sixth-to-last letter and fifth vowel letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''u'' (pronounced ), plural ''ues''. History U derives from the Semitic waw, as does F, and later, Y, W, and V. Its oldest ancestor goes to Egyptian hieroglyphics, and is probably from a hieroglyph of a mace or fowl, representing the sound v.html"_;"title="Voiced_labiodental_fricative.html"_;"title="nowiki/>Voiced_labiodental_fricative">v">Voiced_labiodental_fricative.html"_;"title="nowiki/>Voiced_labiodental_fricative">vor_the_sound_[Voiced_labial–velar_approximant.html" ;"title="Voiced_labiodental_fricative">v.html" ;"title="Voiced_labiodental_fricative.html" ;"title="nowiki/>Voiced labiodental fricative">v">Voiced_labiodental_fricative.html" ;"title="nowiki/>Voiced labiodental fricative">vor the sound [Voiced labial–velar approximant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S Interface
The S interface or S reference point, also known as S0, is a user–network interface reference point in an ISDN BRI environment, characterized by a four-wire circuit using 144kbit/s (2 bearer and 1 signaling channel; 2B+D) user rate. The S interface is the connection between ISDN terminal equipment (TE) or terminal adapters (TAs) and an NT1 (network terminator, type 1.) Not all TE or TAs connect externally to an S interface, but instead integrate an NT1 so they can connect directly to a U interface (local loop from central office.) Contrast to the T interface, which connects between an NT2 (PBX or other local switching device) and NT1. However, the S interface is electrically equivalent to the T interface, and the two are jointly referred to as the S/T interface. The S interface operates at 4000 48-bit frames per second; i.e., 192kbit/s, with a user portion of 36bits per frame; i.e., 144kbit/s.Entry "S interface"/ref> See also * R interface * T interface * U interface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T Interface
A T-interface or T reference point is used for basic rate access in an Integrated Services Digital Network (ISDN) environment. It is a User–network interface reference point that is characterized by a four-wire, 144 kbit/s (2B+D) user rate. Other characteristics of a T-interface are: * it accommodates the link access and transport layer function in the ISDN architecture * it is located at the user premises * it is distance sensitive to the servicing Network termination 1 * it functions in a manner similar to that of the Channel service units (CSUs) and the Data service units (DSUs). The T interface is electrically equivalent to the S interface, and the two are jointly referred to as the S/T interface. See also * R interface * S interface * U interface U or u, is the twenty-first and sixth-to-last letter and fifth vowel letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Customer-premises Equipment
In telecommunications, a customer-premises equipment or customer-provided equipment (CPE) is any terminal and associated equipment located at a subscriber's premises and connected with a carrier's telecommunication circuit at the demarcation point ("demarc"). The demarc is a point established in a building or complex to separate customer equipment from the equipment located in either the distribution infrastructure or central office of the communications service provider. CPE generally refers to devices such as telephones, routers, network switches, residential gateways (RG), set-top boxes, fixed mobile convergence products, home networking adapters and Internet access gateways that enable consumers to access providers' communication services and distribute them in a residence or enterprise with a local area network (LAN). A CPE can be an active equipment, as the ones mentioned above, or passive equipment such as analogue telephone adapters (ATA) or xDSL-splitters. This inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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