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Toll Switching Trunk
In telecommunications, a toll switching trunk or toll connecting trunk is a trunk connecting an end office to a toll center as the first stage of concentration for intertoll or long-distance traffic. Operator assistance or participation may be an optional function. In U.S. common carrier telephony service, a toll center designated ''Class 4C'' is an office where assistance in completing incoming calls is provided in addition to other traffic; a toll center designated ''Class 4P'' is an office where operators handle only outbound calls, or where switching is performed without operator assistance Operator assistance refers to service provided by a telephone operator to the calling party of a telephone call. This can include telephone calls made from pay phones, calls placed ''station-to-station'', ''person-to-person'', or ''collect'', .... References * See also * Class-4 telephone switch Communication circuits Telecommunications economics {{telecomm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunications
Telecommunication, often used in its plural form or abbreviated as telecom, is the transmission of information over a distance using electronic means, typically through cables, radio waves, or other communication technologies. These means of transmission may be divided into communication channels for multiplexing, allowing for a single medium to transmit several concurrent Session (computer science), communication sessions. Long-distance technologies invented during the 20th and 21st centuries generally use electric power, and include the electrical telegraph, telegraph, telephone, television, and radio. Early telecommunication networks used metal wires as the medium for transmitting signals. These networks were used for telegraphy and telephony for many decades. In the first decade of the 20th century, a revolution in wireless communication began with breakthroughs including those made in radio communications by Guglielmo Marconi, who won the 1909 Nobel Prize in Physics. Othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trunk (telecommunications)
In telecommunications, trunking is a technology for providing network access to multiple clients simultaneously by sharing a set of circuits, carriers, channels, or frequencies, instead of providing individual circuits or channels for each client. This is reminiscent to the structure of a tree with one trunk and many branches. Trunking in telecommunication originated in telegraphy, and later in telephone systems where a trunk line is a communications channel between telephone exchanges. Other applications include the trunked radio systems commonly used by police agencies. In the form of link aggregation and VLAN tagging, trunking has been applied in computer networking. Telecommunications A trunk line is a circuit connecting telephone switchboards (or other switching equipment), as distinguished from local loop circuit which extends from telephone exchange switching equipment to individual telephones or information origination/termination equipment. Trunk lines are used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class 5 Telephone Switch
{{No footnotes, date=August 2008 A Class-5 telephone switch is a telephone exchange in the public switched telephone network (PSTN) that directly serves subscribers and manages subscriber calling features. Class-5 services include basic dial-tone, calling features, and additional digital and data services to subscribers connected to a local loop. Function A Class-5 switch provides telephone service to end customers locally in the exchange area, and thus it is concerned with "subscriber type" activities: generation of dial-tone and other "comfort noises"; handling of network services such as advice of duration and charge etc. Specifically, a class-5 switch provides dial tone, local switching and access to the rest of the network. Class-4 switches do not provide subscriber lines, their role is to route calls between other switches. Typically a Class-5 switch serves an area of a city, an individual town, or several villages and could serve from several hundred to 100,000 subscriber ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class 4 Telephone Switch
A class-4, or tandem, telephone switch is a U.S. telephone company central office telephone exchange used to interconnect local exchange carrier offices for long distance communications in the public switched telephone network. A class-4 switch does not connect directly to telephones; instead, it connects to other class-4 switches and to class-5 telephone switches. The telephones of service subscribers are wired to class-5 switches. When a call is placed to a telephone that is not on the same class-5 switch as the originating subscriber, the call may be routed through one or more class-4 switches to reach its destination. Etymology ''Tandem'' derives from the Latin adverb ''tandem'' meaning ''at length'', and is used in English to mean a group of two people or machines working together, usually in series. A tandem switch is used to interconnect other switches via trunks. Thus, tandem switches are always part of a series of switches and lines that connect telephone callers to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long-distance Calling
In telecommunications, a long-distance call (U.S.) or trunk call (also known as a toll call in the UK ) is a telephone call made to a location outside a defined local calling area. Long-distance calls are typically charged a higher billing rate than local calls. The term is not necessarily synonymous with placing calls to another telephone area code. Long-distance calls are classified into two categories: national or domestic calls which connect two points within the same country, and international calls which connect two points in different countries. Within the United States there is a further division into long-distance calls within a single state (intrastate) and interstate calls, which are subject to different regulations (counter-intuitively, calls within states are usually more expensive than interstate calls). Not all interstate calls are long-distance calls. Since 1984 there has also been a distinction between intra- local access and transport area (LATA) calls and those ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operator Assistance
Operator assistance refers to service provided by a telephone operator to the calling party of a telephone call. This can include telephone calls made from pay phones, calls placed ''station-to-station'', ''person-to-person'', or ''collect'', third-number calls, calls billed to credit cards, and certain international calls which cannot be dialed directly. The telephone operator may also be able to assist with determining what kind of technical difficulties are occurring on a phone line, to verify whether a line is busy (''busy line verification'', or ''BLV''), or left off the hook, or to break in on a live call to ask the caller to clear the line for an incoming call ('' busy line interruption'', or ''BLI''). The latter service is often utilized by emergency police. In addition, operators are often a first point of contact for the elderly wanting information on the current date and time. Before the advent of emergency telephone numbers, operators identified and connected emerg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Carrier
A common carrier in common law countries (corresponding to a public carrier in some civil law (legal system), civil law systems,Encyclopædia Britannica CD 2000 "Civil-law public carrier" from "carriage of goods" usually called simply a ''carrier'') is a person or company that transports goods or people for any person or company and is Legal liability, responsible for any possible loss of the goods during transport. A common carrier offers its services to the general public under license or authority provided by a regulatory body, which has usually been granted "ministerial authority" by the legislation that created it. The regulatory body may create, interpret, and enforce its regulations upon the common carrier (subject to judicial review) with independence and finality as long as it acts within the bounds of the enabling legislation. A common carrier (also called a ''public carrier'' in British English) is distinguished from a contract carrier, which is a carrier that transpor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephony
Telephony ( ) is the field of technology involving the development, application, and deployment of telecommunications services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is intimately linked to the invention and development of the telephone. Telephony is commonly referred to as the construction or operation of telephones and telephonic systems and as a system of telecommunications in which telephonic equipment is employed in the transmission of speech or other sound between points, with or without the use of wires. The term is also used frequently to refer to computer hardware, software, and computer network systems, that perform functions traditionally performed by telephone equipment. In this context the technology is specifically referred to as Internet telephony, or voice over Internet Protocol (VoIP). Overview The first telephones were connected directly in pairs: each user had a separate telephone wire ... [...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] |
Operator Assistance
Operator assistance refers to service provided by a telephone operator to the calling party of a telephone call. This can include telephone calls made from pay phones, calls placed ''station-to-station'', ''person-to-person'', or ''collect'', third-number calls, calls billed to credit cards, and certain international calls which cannot be dialed directly. The telephone operator may also be able to assist with determining what kind of technical difficulties are occurring on a phone line, to verify whether a line is busy (''busy line verification'', or ''BLV''), or left off the hook, or to break in on a live call to ask the caller to clear the line for an incoming call ('' busy line interruption'', or ''BLI''). The latter service is often utilized by emergency police. In addition, operators are often a first point of contact for the elderly wanting information on the current date and time. Before the advent of emergency telephone numbers, operators identified and connected emerg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class-4 Telephone Switch
A class-4, or tandem, telephone switch is a U.S. telephone company central office telephone exchange used to interconnect local exchange carrier offices for long distance communications in the public switched telephone network. A class-4 switch does not connect directly to telephones; instead, it connects to other class-4 switches and to class-5 telephone switches. The telephones of service subscribers are wired to class-5 switches. When a call is placed to a telephone that is not on the same class-5 switch as the originating subscriber, the call may be routed through one or more class-4 switches to reach its destination. Etymology ''Tandem'' derives from the Latin adverb ''tandem'' meaning ''at length'', and is used in English to mean a group of two people or machines working together, usually in series. A tandem switch is used to interconnect other switches via trunks. Thus, tandem switches are always part of a series of switches and lines that connect telephone callers to e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communication Circuits
Communication is commonly defined as the transmission of information. Its precise definition is disputed and there are disagreements about whether unintentional or failed transmissions are included and whether communication not only transmits meaning but also creates it. Models of communication are simplified overviews of its main components and their interactions. Many models include the idea that a source uses a coding system to express information in the form of a message. The message is sent through a channel to a receiver who has to decode it to understand it. The main field of inquiry investigating communication is called communication studies. A common way to classify communication is by whether information is exchanged between humans, members of other species, or non-living entities such as computers. For human communication, a central contrast is between verbal and non-verbal communication. Verbal communication involves the exchange of messages in linguistic for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
