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Heat Coil
Heat coils, also known as ''protectors'', ''bugs'' or ''carbons'' serve as a surge protector between the telephone exchange and outside plant. They are commonly the last point of appearance for a telephone circuit before it leaves the office, for example on the outside plant side of the main distribution frame. On some competitive local exchange carrier circuits there are two heat coils, the extra one being at the point of interface between their circuit and where the incumbent local exchange carrier or Regional Bell Operating Company receives it. Their primary purpose is to protect central office equipment from surges of high voltage. If a surge comes down the line it will melt the connection between the central office and outside plant sides, as in a fuse Fuse or FUSE may refer to: Devices * Fuse (electrical), a device used in electrical systems to protect against excessive current ** Fuse (automotive), a class of fuses for vehicles * Fuse (hydraulic), a device used in hyd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surge Protector
A surge protector, spike suppressor, surge suppressor, surge diverter, surge protection device (SPD), transient voltage suppressor (TVS) or transient voltage surge suppressor (TVSS) is an appliance or device intended to protect Electronics, electrical devices in alternating current (AC) circuits from voltage spikes with very short duration measured in microseconds, which can arise from a variety of causes including lightning strikes in the vicinity. A surge protector limits the voltage supplied to the electrical devices to a certain threshold by short-circuiting current to Ground (electricity), ground or absorbing the spike when a transient occurs, thus avoiding damage to the devices connected to it. Key specifications that characterize this device are the clamping voltage, or the transient voltage at which the device starts functioning, the Joule rating, a measure of how much energy can be absorbed per surge, and the response time. Definitions The terms ''surge protection d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone Exchange
A telephone exchange, telephone switch, or central office is a central component of a telecommunications system in the public switched telephone network (PSTN) or in large enterprises. It facilitates the establishment of communication circuits, enabling telephone calls between subscribers. The term "central office" can also refer to a central location for fiber optic equipment for a fiber internet provider. In historical perspective, telecommunication terminology has evolved with time. The term ''telephone exchange'' is often used synonymously with ''central office'', a Bell System term. A central office is defined as the telephone switch controlling connections for one or more central office prefixes. However, it also often denotes the building used to house the inside plant equipment for multiple telephone exchange areas. In North America, the term ''wire center'' may be used to denote a central office location, indicating a facility that provides a telephone with a dial tone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outside Plant
In telecommunications, the term outside plant has the following meanings: *In civilian telecommunications, outside plant refers to all of the physical cabling and supporting infrastructure (such as conduit, cabinets, tower or poles), and any associated hardware (such as repeaters) located between a demarcation point in a switching facility and a demarcation point in another switching center or customer premises. *In the United States, the DOD defines outside plant as the communications equipment located between a main distribution frame (MDF) and a user end instrument. The CATV industry divides its fixed assets between head end or inside plant, and outside plant. The electrical power industry also uses the term outside plant to refer to electric power distribution systems. Context Network connections between devices such as computers, printers, and phones require a physical infrastructure to carry and process signals. Typically, this infrastructure will consist o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Point Of Appearance
Point of appearance is a generic term for any point in a telephone/data circuit from which a technician can test or pull stats. Some appearances are virtual, such as a Digital cross connect system computer terminal. Others are physical, like a punch down COSMIC frame where a technician can place a test set, or a heat coil socket. In the outside plant there is an appearance at the cross box, pedestal, and network interface device. The ultimate appearance is the telephone or other customer premises equipment (CPE). See also *Demarcation point *Point of presence A point of presence (PoP) is an artificial demarcation point or network interface point between communicating entities. A common example is an ISP point of presence, the local access point that allows users to connect to the Internet with their ... References Communication circuits {{Tech-stub ... [...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 consistent 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 using two-wire circuits, called the local loop, from each user's telephone to end offices, which performed a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Main Distribution Frame
In telephony, a main distribution frame (MDF or main frame) is a signal distribution frame for connecting equipment (inside plant) to cables and subscriber carrier equipment ( outside plant). Overview The MDF is a termination point within the local telephone exchange where exchange equipment and terminations of local loops are connected by jumper wires at the MDF. All cable copper pairs supplying services through user telephone lines are terminated at the MDF and distributed through the MDF to equipment within the local exchange e.g. repeaters and DSLAM. Cables to intermediate distribution frames (IDF) terminate at the MDF. Trunk cables may terminate on the same MDF or on a separate trunk main distribution frame (TMDF). Like other distribution frames the MDF provides flexibility in assigning facilities, at lower cost and higher capacity than a patch panel. The most common kind of large MDF is a long steel rack accessible from both sides. On one side, termination blocks a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Competitive Local Exchange Carrier
A competitive local exchange carrier (CLEC) is a North American telecommunications provider classification that emerged based on the competition model of the Telecommunications Act of 1996 in the United States. The act required the previously established incumbent local exchange carrier (ILEC) in each local market to provide infrastructure hosting and services to CLECs to enable competition with the ILEC. Background Local exchange carriers (LECs) are characterized as incumbent (ILECs) or competitive (CLECs). The ILECs are usually the original, monopoly LEC in a given area, and receive different regulatory treatment from the newer CLECs. A data local exchange carrier (DLEC) is a CLEC specializing in DSL services by leasing lines from the ILEC and reselling them to Internet service providers (ISPs). History CLECs evolved from the competitive access providers (CAPs) that began to offer private line and special access services in competition with the ILECs beginning in 1985. The CA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incumbent Local Exchange Carrier
An incumbent local exchange carrier (ILEC) is a local telephone company which held the regional monopoly on landline service before the market was opened to competitive local exchange carriers, or the corporate successor of such a firm, in the United States and Canada. Definition An incumbent local exchange carrier is a local exchange carrier (LEC) in a specific area that * on the date of enactment of the Telecommunications Act of 1996, provided telephone exchange service * on the date of enactment, was deemed to be a member of the National Exchange Carrier Association pursuant to the Code of Federal Regulations (C.F.R) Title 47, section 69.601(b). * or is a person or entity that, on or after such date of enactment, became a successor or assignee of a member described in the previous bullet. The Federal Communications Commission (FCC) may, by rule, provide for the treatment of an LEC (or class or category thereof) as an ILEC if: * such carrier occupies a position in the marke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regional Bell Operating Company
A Regional Bell Operating Company (RBOC) was a corporate entity created as result of the antitrust lawsuit by the United States Department of Justice against the Western Electric Company and American Telephone and Telegraph Company (AT&T) in 1949 and a suit in 1974 against AT&T ('' United States v. AT&T''). The suits were settled in the Modification of Final Judgment in August 1982. AT&T agreed to divest its local exchange service operating companies, effective January 1, 1984. The group of local operating companies were split into seven independent Regional Bell Operating Companies, which became known as the Baby Bells. Three companies still exist that have an RBOC as a predecessor: AT&T, Verizon, and Lumen Technologies (formerly CenturyTel and CenturyLink). Some other companies are holding onto smaller segments of the companies. Baby Bells A "Baby Bell" is a local telephone company in the United States that was in existence at the time of the breakup of AT&T into the resulti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voltage Spike
In electrical engineering, spikes are fast, short duration electrical transients in voltage (voltage spikes), current (current spikes), or transferred energy (energy spikes) in an electrical circuit. Fast, short duration electrical transients ( overvoltages) in the electric potential of a circuit are typically caused by * Lightning strikes * Power outages * Tripped circuit breakers * Short circuits * Power transitions in other large equipment on the same power line * Malfunctions caused by the power company * Electromagnetic pulses (EMP) with electromagnetic energy distributed typically up to the 100 kHz and 1 MHz frequency range. * Inductive spikes In the design of critical infrastructure and military hardware, one concern is of pulses produced by nuclear explosions, whose nuclear electromagnetic pulses distribute large energies in frequencies from 1 kHz into the gigahertz range through the atmosphere. The effect of a voltage spike is to produce a correspo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fuse (electrical)
In electronics and electrical engineering, a fuse is an electrical safety device that operates to provide overcurrent protection of an electrical circuit. Its essential component is a metal wire or strip that melts when too much current flows through it, thereby stopping or interrupting the current. It is a sacrificial device; once a fuse has operated, it is an open circuit, and must be replaced or rewired, depending on its type. Fuses have been used as essential safety devices from the early days of electrical engineering. Today there are thousands of different fuse designs which have specific current and voltage ratings, breaking capacity, and response times, depending on the application. The time and current operating characteristics of fuses are chosen to provide adequate protection without needless interruption. Wiring regulations usually define a maximum fuse current rating for particular circuits. A fuse can be used to mitigate short circuits, overloading, mismatched loads ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
