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Basic Analog Loop
A dry loop is an unconditioned leased pair of telephone line from a telephone company. The pair does not provide dial tone or battery (continuous electric potential), as opposed to a wet pair, a line usually without dial tone but with battery. A dry pair was originally used with a security system but more recently may also be used with digital subscriber line (DSL) service or an Ethernet extender to connect two locations, as opposed to a costlier means such as a Frame Relay. The pair in many cases goes through the local telephone exchange. ''Wet pair'' naming comes from the battery used to sustain the loop, which was made from wet cells. Many carriers market dry loops to independent DSL providers as a BANA for basic analog loop or in some locales PANA for plain analog loop, OPX (off-premises extension) line, paging circuit, or finally LADS (local area data service). Local availability In the United States, these circuits typically incur a monthly recurring charge of $3.00 p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leased Line
A leased line is a private telecommunications circuit between two or more locations provided according to a commercial contract. It is sometimes also known as a private circuit, and as a data line in the UK. Typically, leased lines are used by businesses to connect geographically distant offices. Unlike traditional telephone lines in the public switched telephone network (PSTN) leased lines are generally not switched circuits, and therefore do not have an associated telephone number. Each side of the line is permanently connected, always active and dedicated to the other. Leased lines can be used for telephone, Internet, or other data communication services. Some are ringdown services, and some connect to a private branch exchange (PBX) or network router. The primary factors affecting the recurring lease fees are the distance between end stations and the bandwidth of the circuit. Since the connection does not carry third-party communications, the carrier can assure a specified ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications In The United States
The primary regulator of communications in the United States is the Federal Communications Commission. It closely regulates all of the industries mentioned below with the exception of newspapers and the Internet service provider industry. History The Federal Communications Commission (FCC) is an independent government agency responsible for regulating the radio, television and phone industries. The FCC regulates all interstate communications, such as wire, satellite and cable, and international communications originating or terminating in the United States. Press Newspapers declined in their influence and penetration into American households in the late 20th century. Most newspapers are local, having little circulation outside their particular metropolitan area. The closest thing to a national paper the U.S. has is ''USA Today''. Other influential dailies include ''The New York Times'', ''The Washington Post'' and ''The Wall Street Journal'' which are sold in most U.S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Local-loop Unbundling
Local loop unbundling (LLU or LLUB) is the regulatory process of allowing multiple telecommunications operators to use connections from the telephone exchange to the customer's premises. The physical wire connection between the local exchange and the customer is known as a "local loop", and is owned by the incumbent local exchange carrier (also referred to as the "ILEC", "local exchange", or in the United States either a "Baby Bell" or an independent telephone company). To increase competition, other providers are granted unbundled access. Policy background LLU is generally opposed by the ILECs, which in most cases are either former investor-owned (North America) or state-owned monopoly enterprises forced to open themselves to competition. ILECs argue that LLU amounts to a regulatory taking, that they are forced to provide competitors with essential business inputs, that LLU stifles infrastructure-based competition and technical innovation because new entrants prefer to 'parasiti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Current Loop
In electrical signalling an analog current loop is used where a device must be monitored or controlled remotely over a pair of conductors. Only one current level can be present at any time. A major application of current loops is the industry de facto standard 4–20 mA current loop for process control applications, where they are extensively used to carry signals from process instrumentation to PID controllers, SCADA systems, and programmable logic controllers (PLCs). They are also used to transmit controller outputs to the modulating field devices such as control valves. These loops have the advantages of simplicity and noise immunity, and have a large international user and equipment supplier base. Some 4–20 mA field devices can be powered by the current loop itself, removing the need for separate power supplies, and the "smart" HART protocol uses the loop for communications between field devices and controllers. Various automation protocols may replace analog cur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
9-1-1
, usually written 911, is an emergency telephone number for the United States, Canada, Mexico, Panama, Palau, Argentina, Philippines, Jordan, as well as the North American Numbering Plan (NANP), one of eight N11 codes. Like other emergency numbers around the world, this number is intended for use in emergency circumstances only. Using it for any other purpose (such as making false or prank calls) is a crime in most jurisdictions. In over 98% of locations in Argentina, Panama, Belize, Anguilla, Costa Rica, Ecuador, Jordan, Ethiopia, Liberia, Saudi Arabia, Philippines, Uruguay, United States, Palau, Mexico, Tonga and Canada, dialing "9-1-1" from any telephone will link the caller to an emergency dispatch office—called a Public Safety Answering Point (PSAP) by the telecommunications industry—which can send emergency responders to the caller's location in an emergency. In approximately 96 percent of the United States, the enhanced 9-1-1 system automatically pairs caller ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Automatic Number Announcement Circuit
An automatic number announcement circuit (ANAC) is a component of a central office of a telephone company that provides a service to installation and service technicians to determine the telephone number of a telephone line. The facility has a telephone number that may be called to listen to an automatic announcement that includes the caller's telephone number. The ANAC facility is useful primarily during the installation of landline telephones to quickly identify one of multiple wire pairs in a bundle or at a termination point. Operation By connecting a test telephone set, a technician calls the local telephone number of the automatic number announcement service. This call is connected to equipment at the central office that uses automatic equipment to announce the telephone number of the line calling in. The main purpose of this system is to allow telephone company technicians to identify the telephone line they are connected to. Automatic number announcement systems are base ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cable Modem
A cable modem is a type of network bridge that provides bi-directional data communication via radio frequency channels on a hybrid fibre-coaxial (HFC), radio frequency over glass (RFoG) and coaxial cable infrastructure. Cable modems are primarily used to deliver broadband Internet access in the form of cable Internet, taking advantage of the high bandwidth of a HFC and RFoG network. They are commonly deployed in the Americas, Asia, Australia, and Europe. History MITRE Cablenet Internet Experiment Note (IEN) 96IEN 96 - The Cablenet Project (1979) describes an early RF cable modem system. From pages 2 and 3 of IEN 96: The ... |
Naked DSL
A naked DSL, also known as standalone or dry loop DSL, is a digital subscriber line (DSL) without a PSTN ( analogue telephony) service — or the associated dial tone. In other words, only a standalone DSL Internet service is provided on the local loop. The original concept of DSL was to use existing telephone lines for high speed data communication, with DSL and telephone services coexisting on the same phone line - but increasingly customers may require ''only'' the Internet service - and see no need for the traditional phone service. Comparison of Regular and Naked DSL (Standalone DSL) In Regular DSL, data transmission is carried on inaudible high frequencies on a standard Plain Old Telephone Service (POTS) telephone line. The original idea was to use existing telephone lines for high speed data communication. DSL and telephone service can coexist on the same phone line and do not interfere with each other. From the Telco's point of view, DSL gives them the ability ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell Canada
Bell Canada (commonly referred to as Bell) is a Canadian telecommunications company headquartered at 1 Carrefour Alexander-Graham-Bell in the borough of Verdun in Montreal, Quebec, Canada. It is an ILEC (incumbent local exchange carrier) in the provinces of Ontario and Quebec; as such, it was a founding member of the Stentor Alliance. It is also a CLEC (competitive local exchange carrier) for enterprise customers in the western provinces. Its subsidiary Bell Aliant provides services in the Atlantic provinces. It provides mobile service through its Bell Mobility (including flanker brand Virgin Mobile Canada) subsidiary, and television through its Bell Satellite TV (direct broadcast satellite) and Bell Fibe TV (IPTV) subsidiaries. Bell Canada's principal competitors are Rogers Communications in Ontario, Telus and Shaw Communications in Western Canada, and Quebecor ( Videotron) and Telus in Quebec. The company serves over 13 million phone lines and is headquartered at the ... [...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] |
Telephone Line
A telephone line or telephone circuit (or just line or circuit industrywide) is a single-user circuit on a telephone communication system. It is designed to reproduce speech of a quality that is understandable. It is the physical wire or other signaling medium connecting the user's telephone apparatus to the telecommunications network, and usually also implies a single telephone number for billing purposes reserved for that user. Telephone lines are used to deliver landline telephone service and Digital subscriber line (DSL) phone cable service to the premises. Telephone overhead lines are connected to the public switched telephone network. The voltage at a subscriber's network interface is typically 48 V between the ring and tip wires, with tip near ground and ring at -48 V. In the United States In 1878, the Bell Telephone Company began to use two-wire circuits, called the local loop, from each user's telephone to end offices which performed any necessary electrical s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frame Relay
Frame Relay is a standardized wide area network (WAN) technology that specifies the physical and data link layers of digital telecommunications channels using a packet switching methodology. Originally designed for transport across Integrated Services Digital Network (ISDN) infrastructure, it may be used today in the context of many other network interfaces. Network providers commonly implement Frame Relay for voice (VoFR) and data as an encapsulation technique used between local area networks (LANs) over a WAN. Each end-user gets a private line (or leased line) to a Frame Relay node. The Frame Relay network handles the transmission over a frequently changing path transparent to all end-user extensively used WAN protocols. It is less expensive than leased lines and that is one reason for its popularity. The extreme simplicity of configuring user equipment in a Frame Relay network offers another reason for Frame Relay's popularity. With the advent of Ethernet over fiber optics, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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