|
Limited Availability
When customers of a public switched telephone network make telephone calls, they utilize a telecommunications network called a switched-circuit network. In a switched-circuit network, devices known as switches are used to connect the calling party to the called party. Each switch has a number of inlets and outlets, and by connecting a specific inlet to the correct outlet, each switch helps to complete an end-to-end circuit between users. This method is used in, for example graded multiple banks of selectors. Bell System Technical Journal, Jan 1970, pp 135-165 In a modern circuit-switched network, |
Public Switched Telephone Network
The public switched telephone network (PSTN) provides infrastructure and services for public telecommunication. The PSTN is the aggregate of the world's circuit-switched telephone networks that are operated by national, regional, or local telephony operators. These consist of telephone lines, fiber optic cables, microwave transmission links, cellular networks, communications satellites, and undersea telephone cables, all interconnected by switching centers which allow most telephones to communicate with each other. Originally a network of fixed-line analog telephone systems, the PSTN is now almost entirely digital in its core network and includes mobile and other networks, as well as fixed telephones. The technical operation of the PSTN adheres to the standards created by the ITU-T. These standards allow different networks in different countries to interconnect seamlessly. The E.163 and E.164 standards provide a single global address space for telephone numbers. The com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone Call
A telephone call is a connection over a telephone network between the called party and the calling party. First telephone call The first telephone call was made on March 10, 1876, by Alexander Graham Bell. Bell demonstrated his ability to "talk with electricity" by transmitting a call to his assistant, Thomas Watson. The first words transmitted were "Mr Watson, come here. I want to see you." This event has been called Bell's "greatest success", as it demonstrated the first successful use of the telephone. Although it was his greatest success, he refused to have a telephone in his own home because it was something he invented by mistake and saw it as a distraction from his main studies. Information transmission A telephone call may carry ordinary voice transmission using a telephone, data transmission when the calling party and called party are using modems, or facsimile transmission when they are using fax machines. The call may use land line, mobile phone, satellit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunications Network
A telecommunications network is a group of nodes interconnected by telecommunications links that are used to exchange messages between the nodes. The links may use a variety of technologies based on the methodologies of circuit switching, message switching, or packet switching, to pass messages and signals. Multiple nodes may cooperate to pass the message from an originating node to the destination node, via multiple network hops. For this routing function, each node in the network is assigned a network address for identification and locating it on the network. The collection of addresses in the network is called the address space of the network. Examples of telecommunications networks include computer networks, the Internet, the public switched telephone network (PSTN), the global Telex network, the aeronautical ACARS network, and the wireless radio networks of cell phone telecommunication providers. Network structure In general, every telecommunications network conce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circuit Switching
Circuit switching is a method of implementing a telecommunications network in which two network nodes establish a dedicated communications channel (circuit) through the network before the nodes may communicate. The circuit guarantees the full bandwidth of the channel and remains connected for the duration of the communication session. The circuit functions as if the nodes were physically connected as with an electrical circuit. Circuit switching originated in analog telephone networks where the network created a dedicated circuit between two telephones for the duration of a telephone call. It contrasts with message switching and packet switching used in modern digital networks in which the trunklines between switching centers carry data between many different nodes in the form of data packets without dedicated circuits. Description The defining example of a circuit-switched network is the early analog telephone network. When a call is made from one telephone to another, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calling Party
The calling party (in some contexts called the "A-Number") is a person who (or device that) initiates a telephone call. The person who, or device that, receives a telephone call is the called party (or callee or B-party). In some countries, it is common etiquette for a call originator to identify himself first instead of the receiver, when the connection is established. Modem A modulator-demodulator or modem is a computer hardware device that converts data from a digital format into a format suitable for an analog transmission medium such as telephone or radio. A modem transmits data by modulating one or more c ...s and fax machines use different tones when originating or answering a connection, which may be a source of problems for the user. Telephony Teletraffic {{telephony-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Called Party
The called party (in some contexts called the "B-Number") is a person who (or device that) answers a telephone call. The person who (or device that) initiates a telephone call is the calling party. In some situations, the called party may number more than one. Such an instance is known as a conference call. In some systems, only one called party is contacted at each event. To initiate a conference call the calling party contacts the first called party, then this person contacts the second called party, but audio is transferred to both called parties. In a collect call (i.e. reverse charge), the called party pays the fee for the call, when it is usually the calling party that does so. The called party also pays if the number dialed is a toll-free telephone number. In some countries such as Canada, the United States and China, users of mobile phone A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circuit-switched
Circuit switching is a method of implementing a telecommunications network in which two network nodes establish a dedicated communications channel (circuit) through the network before the nodes may communicate. The circuit guarantees the full bandwidth of the channel and remains connected for the duration of the communication session. The circuit functions as if the nodes were physically connected as with an electrical circuit. Circuit switching originated in analog telephone networks where the network created a dedicated circuit between two telephones for the duration of a telephone call. It contrasts with message switching and packet switching used in modern digital networks in which the trunklines between switching centers carry data between many different nodes in the form of data packets without dedicated circuits. Description The defining example of a circuit-switched network is the early analog telephone network. When a call is made from one telephone to another, swit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone Exchange
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 def ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Telephone Exchange")