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A choke exchange is a telephone exchange designed to handle many simultaneous call attempts to telephone numbers of that exchange. Choke exchanges are typically used to service telephone numbers of talk radio caller and contest lines of radio stations [1] and event ticket vendors.
A central office might only have physical plant resources to handle ca. 8% of allocated telephone numbers, based on historical call traffic averages. A choke exchange has trunk facilities to other exchanges designed in a manner that high call volume is handled through the choke connection rather than overwhelming the rest of the local telephone network. Other local exchanges have a limited number of direct trunks (junctions) to the choke exchange, which may only serve one or more customers, such as a radio station contest line, which may experience many simultaneous calls. But instead of calls being overflowed to main or tandem routes shared with other calls, the unsuccessful callers receive a reorder tone from their local or tandem exchange. If the calls were overflowed to the tandem route, the caller would receive a busy tone from the exchange serving the radio station, and the sudden peak would disrupt calls between other customers.
With common-channel signaling (CCS), e.g., Signalling System No. 7, separate choke exchanges may not be required for these customers.
Examples of choke exchanges in North America have included:
One of the early choke lines (exchanges) was instituted due to a widely advertised contest by a local radio station in the Miami/Fort Lauderdale area. WHYI-FM advertised their "Last Contest". The top prize was an automobile. Since the advertising lasted over a month, there were a very large volume of calls when they announced for people to call in. There were so many calls that the local exchanges ran out of dial tones. This caused major issues since at the time if a caller had no dial tone, the caller could not dial at all. After it was over, the area emergency services filed complaints, and were heard. Shortly afterward the 305-550 exchange came into being. The first number on it was 305-550-9100 (for Y100 radio station). Due to the issues involved because of the "Last Contest", this may have been what caused the creation of the choke exchanges.
Caller identification is a telephone service, available in analog and digital telephone systems, including voice over IP (VoIP), that transmits a caller's telephone number to the called party's telephone equipment when the call is being set up. The caller ID service may include the transmission of a name associated with the calling telephone number, in a service called Calling Name Presentation (CNAM). The service was first defined in 1993 in International Telecommunication Union – Telecommunication Standardization Sector (ITU-T) Recommendation Q.731.3.
A blue box is an electronic device that produces tones used to generate the in-band signaling tones formerly used within the North American long-distance telephone network to send line status and called number information over voice circuits. This allowed an illicit user, referred to as a "phreaker", to place long-distance calls, without using the network's user facilities, that would be billed to another number or dismissed entirely as an incomplete call. A number of similar "color boxes" were also created to control other aspects of the phone network.
Premium-rate telephone numbers are telephone numbers that charge callers higher price rates for select services, including information and entertainment. A portion of the call fees is paid to the service provider, allowing premium calls to be an additional source of revenue for businesses. Tech support, psychic hotlines, and adult chat lines are among the most popular kinds of premium-rate phone services. Other services include directory enquiries, weather forecasts, competitions and ratings televoting. Some businesses, e.g. low-cost airlines, and diplomatic missions, such as the US Embassy in London or the UK Embassy in Washington, have also used premium-rate phone numbers for calls from the general public.
A telephone call or telephone conversation, also known as a phone call or voice call, is a connection over a telephone network between the called party and the calling party. Telephone calls started in the late 19th century. As technology has improved, a majority of telephone calls are made over a cellular network through mobile phones or over the internet with Voice over IP. Telephone calls are typically used for real-time conversation between two or more parties, especially when the parties cannot meet in person.
A toll-free telephone number or freephone number is a telephone number that is billed for all arriving calls. For the calling party, a call to a toll-free number from a landline is free of charge. A toll-free number is identified by a dialing prefix similar to an area code. The specific service access varies by country.
Ten-digit dialing is a telephone dialing procedure in the countries and territories that are members of the North American Numbering Plan (NANP). It is the practice of including the area code of a telephone number when dialing to initiate a telephone call. When necessary, the ten-digit number may be prefixed with the trunk code 1, which is referred to as 1+10-digit dialing or national format.
Trunk and toll calling were two alternative methods of charging customers for long-distance calls in the United Kingdom in the first half of the 20th century. The distinction became obsolete with the introduction of subscriber trunk dialling (STD).
In telecommunications, a long-distance call (U.S.) or trunk call 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.
Alex was the name of an interactive videotex information service offered by Bell Canada in market research from 1988 to 1990 and thence to the general public until 1994.
Numbers on the Irish telephone numbering plan are regulated and assigned to operators by ComReg.
The New Zealand telephone numbering plan describes the allocation of telephone numbers in New Zealand and the Pitcairn Islands.
Foreign exchange service (FX) is an access service in a telecommunications network in which a telephone in a given exchange area is connected, via a private line, as opposed to a switched line, to a telephone exchange or central office in another exchange area, called the foreign exchange, rather than the local exchange area where the subscriber station equipment is located.
Telephone numbers in Italy are managed by the Autorità per le Garanzie nelle Comunicazioni (AGCOM), a national regulatory authority for the communication industry located in Rome.
Telephone numbers in Russia are administered by Roskomnadzor, and Ministry of Digital Development, Communications and Mass Communications of the Russian Federation. Russia's National Numbering Plan (NNP) is a four-level telephone numbering plan with local, zone, country, and international scopes, implementing a closed numbering plan, in which the number of digits of all national significant numbers (NSN) assigned to subscriber telephones is fixed at ten, with three digits for the area code, and a seven-digit subscriber number which includes a zone code of up to two digits. Internationally, Russia participates in the numbering plans of the International Telecommunication Union (ITU) provided by recommendations E.164 and E.123, using the telephone country code 7.
The line information database (LIDB) is a collection of commercial databases used in the United States and Canada by telephone companies to store and retrieve Calling Name Presentation (CNAM) data used for caller ID services. In Canada, it is common for the client to apply their own Caller ID information, and this is allowed, provided the regulations regarding spoofing and fraud are not violated. The databases map telephone numbers to 15-character strings of caller names. Class 5 telephone switches, which provide end-office services in exchange areas, use the Signaling System 7 (SS7) signaling protocol to query the database.
A telephone number is a sequence of digits assigned to a landline telephone subscriber station connected to a telephone line or to a wireless electronic telephony device, such as a radio telephone or a mobile telephone, or to other devices for data transmission via the public switched telephone network (PSTN) or other public and private networks.
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.
Caller Name Presentation (CNAP) or Caller Name Delivery (CNAM) is used in US-based telephone networks to provide name identification of the calling party. The CNAM information is most often displayed in Caller ID. The information could be the person's name or a company name. The caller's name can also be blocked and display “restricted”, or if technical failures occur “not available”.