In telecommunication Telecommunication is the transmission of signals over a distance for the purpose of communication. In earlier times, this may have involved the use of smoke signals, drums, semaphore, flags or heliograph. In modern times, telecommunication typically involves the use of electronic devices such as telephones, television, radio or computers. Early, telephony (pronounced /təˈlɛfəni/ or teh-LEH-fuh-nee) encompasses the general use of equipment to provide voice communication over distances, specifically by connecting telephones The telephone is a telecommunications device that transmits and receives sound, most commonly the human voice. It is one of the most common household appliances in the developed world, and has long been considered indispensable to business, industry and government. The word "telephone" has been adapted to many languages and is widely to each other.
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History
Telephones were originally connected directly together in pairs. Each user had separate telephones wired to the various places he might wish to reach. This became inconvenient when people wanted to talk to many other telephones, so the telephone exchange In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls. A central office is the physical building used to house inside plant equipment including telephone switches, which make telephone calls "work" in the sense of making connections and relaying the was invented. Each telephone could then be connected to other local ones, thus inventing the local loop In telephony, the local loop is the physical link or circuit that connects from the demarcation point of the customer premises to the edge of the carrier or telecommunications service provider's network. At the edge of the carrier access network in a traditional PSTN (Public Switched Telephone Network) scenario, the local loop terminates in a and the telephone call A telephone call is a connection over a telephone network between the calling party and the called party. Soon, nearby exchanges were connected by trunk lines In modern communications, trunking is a concept by which a communications system can provide network access to many clients by sharing a set of lines or frequencies instead of providing them individually. This is analogous to the structure of a tree with one trunk and many branches. Examples of this include telephone systems and the VHF radios, and eventually distant ones were as well.
In modern times, most telephones are plugged into telephone jacks Telephone jacks are the sockets that receive the telephone plugs on the manual telephone switchboards. The jacks are connected by inside wiring In telecommunication, on-premises wiring is customer-owned communications transmission lines. It is also called customer premises wiring . The transmission lines can be metallic (copper) or optical fiber, and may be installed within or between buildings to a drop In a communications network, a drop is the portion of a device directly connected to the internal station facilities, such as toward a telephone switchboard, toward a switching center, or toward a telephone exchange. A drop can also be a wire or cable from a pole or cable terminus to a building wire which connects the building to a cable. Cables usually bring a large number of drop wires from all over a district access network An access network is that part of a communications network which connects subscribers to their immediate service provider. It is contrasted with the core network, for example the Network Switching Subsystem in GSM. The access network may be further divided between feeder plant or distribution network, and drop plant or edge network to one wire center or telephone exchange. When the user of a telephone wants to make a telephone call A telephone call is a connection over a telephone network between the calling party and the called party, equipment at the exchange examines the dialed telephone number A telephone number or phone number is a sequence of numbers used to call from one telephone line to another in a public switched telephone network. When telephone numbers were invented, they were short — as few as one, two or three digits — and were given verbally to a switchboard operator. As phone systems have grown and interconnected to and connects that telephone line A telephone line or telephone circuit is a single-user circuit on a telephone communications system. Typically this refers to 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 to another in the same wire center, or to a trunk to a distant exchange. Most of the exchanges in the world are connected to each other, forming the public switched telephone network The public switched telephone network is the network of the world's public circuit-switched telephone networks. Originally a network of fixed-line analog telephone systems, the PSTN is now almost entirely digital in its core and includes mobile as well as fixed (plain old telephone service, POTS) telephones (PSTN). By the end of the 20th century almost all were Stored Program Control exchanges Stored Program Control exchange is the technical name used for telephone exchanges controlled by a computer program stored in the memory of the system. Early exchanges such as Strowger, panel, rotary, and crossbar switches were electromechanical and had no software control. SPC was introduced on a small scale in so called electronic switching.
After the middle 20th century fax and data became important secondary users of the network created to carry voices, and late in the century parts of the network were upgraded with ISDN Integrated services digital network is a set of communications standards enabling traditional telephone lines to carry voice, digital network services, and video. Prior to ISDN, the phone system was viewed as a way to transport voice, with some special services available for data. The key feature of the ISDN is that it integrates speech and data and DSL DSL or xDSL is a family of technologies that provides digital data transmission over the wires of a local telephone network. DSL originally stood for digital subscriber loop, but as of 2009[update] the term digital subscriber line has been widely adopted as a more marketing-friendly term for Asymmetric Digital Subscriber Line , the most popular to improve handling of such traffic.
Digital telephony Digital telephony is the use of digital electronics in the provision of digital telephone services and systems. Since the 1960s a digital core network has almost entirely replaced the old analog system, and much of the access network has also been digitized. Digital telephony was introduced to provide voice services at lower cost, but was then is the use of digital technology in the provision of telephone services and systems. Almost all telephone calls are provided this way, but sometimes the term is restricted to cases in which the last mile The "last mile" or "last kilometre" is the final leg of delivering connectivity from a communications provider to a customer. The phrase is therefore often used by the telecommunications and cable television industries. The actual distance of this leg may be considerably more than a mile, especially in rural areas. It is is digital, or where the conversion between digital and analog signals takes place inside the telephone. Telephony was digitized to cut the cost and improve the quality of voice services, but digital telephony was then found useful for new network services (ISDN Integrated Services Digital Network is a telephone system network. Prior to the ISDN, the phone system was viewed as a way to transport voice, with some special services available for data. The key feature of the ISDN is that it integrates speech and data on the same lines, adding features that were not available in the classic telephone system) to transfer data speedily over telephone lines.
Recent developments
IP telephony Voice over Internet Protocol is a general term for a family of transmission technologies for delivery of voice communications over IP networks such as the Internet or other packet-switched networks. Other terms frequently encountered and synonymous with VoIP are IP telephony, Internet telephony, voice over broadband (VoBB), broadband telephony, is a modern form of telephony which uses the TCP/IP The Internet Protocol Suite is the set of communications protocols used for the Internet and other similar networks. It is named from two of the most important protocols in it: the Transmission Control Protocol (TCP) and the Internet Protocol (IP), which were the first two networking protocols defined in this standard. Today's IP networking protocol popularized by the Internet The Internet is a global system of interconnected computer networks that use the standard Internet Protocol Suite to serve billions of users worldwide. It is a network of networks that consists of millions of private and public, academic, business, and government networks of local to global scope that are linked by a broad array of electronic and to transmit digitized voice data. Contrast this with the operation of POTS (an acronym for "plain old telephone service Plain old telephone service is the voice-grade telephone service that remains the basic form of residential and small business service connection to the telephone network in most parts of the world. The name is a retronym, and is a reflection of the telephone service still available after the advent of more advanced forms of telephony such as ISDN,").
Computer telephony integration Computer telephony integration, also called computer–telephone integration or CTI, is technology that allows interactions on a telephone and a computer to be integrated or co-ordinated. As contact channels have expanded from voice to include email, web, and fax, the definition of CTI has expanded to include the integration of all customer (CTI) enables computers to know about and control phone functions such as making and receiving voice, fax, and data calls with telephone directory A telephone directory is a listing of telephone subscribers in a geographical area or subscribers to services provided by the organization that publishes the directory services and caller identification. The integration of telephone software and computer systems is a major development in the evolution of the automated office.
CTI is not a new concept. Such links have been used in the past in large telephone networks but only dedicated call centers A call centre or call center is a centralised office used for the purpose of receiving and transmitting a large volume of requests by telephone. A call centre is operated by a company to administer incoming product support or information inquiries from consumers. Outgoing calls for telemarketing, clientele, product services, and debt collection could justify the costs of the required equipment installation. Primary telephone service providers are offering information services such as automatic number identification Automatic Number Identification is a feature of telephony intelligent network services that permits subscribers to display or capture the telephone numbers of calling parties. In the United States it is part of Inward Wide Area Telephone Service (WATS). The ANI service was created by AT&T for internal long distance billing purposes, and is not (ANI) and Dialed Number Identification Service Dialed Number Identification Service is a service sold by telecommunications companies to corporate clients that lets them determine which telephone number was dialed by a customer. This is useful in determining how to answer an inbound call. The Telecommunications company sends a DNIS number to the client phone system during the call setup. The (DNIS) on a scale wide enough for its implementation to bring real value to business or residential telephone usage. A new generation of applications (middleware Middleware is a computer software that connects software components or applications. The software consists of a set of services that allows multiple processes running on one or more machines to interact. This technology evolved to provide for interoperability in support of the move to coherent distributed architectures, which are used most often) is being developed as a result of standardization and availability of low cost computer telephony links.
See also
- List of telephony terminology Contents: Top · 0–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
- History of the telephone Before the invention of electromagnetic telephones, there were mechanical devices for transmitting spoken words over a greater distance than that of normal speech. The very earliest mechanical telephones were based on sound transmission through pipes or other physical media. Speaking tubes long remained common, including a lengthy history of use
- Invention of the telephone The modern telephone is the culmination of work done by many individuals, all worthy of recognition for their contributions to the field. Alexander Graham Bell was the first to patent the telephone, an "apparatus for transmitting vocal or other sounds telegraphically", after experimenting with many primitive sound transmitters and
References
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Categories: Telephony Categories: Telecommunications | Electronic engineering | Telecommunications history The history of telecommunication including radio, telegraphy, television, telephony, data communication and computer networking
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Your smartphone today is a data device that happens to run a lot of applications, which include both . telephony. and television. Yet the bill you get for using your phone (no matter how smart it is) comes from a phone company. ...
Q. How i use internet telephony,in india for free?
Asked by NITIN DONGRE - Mon Apr 17 05:10:55 2006 - - 2 Answers - 0 Comments
A. With the help of Skype or google talk u can talk to a people who r online. But if u want to call someone who has landline or mobile u have to pay some money.
Answered by generation - Mon Apr 17 05:20:18 2006
