Subscriber trunk dialling
Encyclopedia
Subscriber trunk dialling (STD, also known as subscriber toll dialling) is a term for a telephone
Telephone
The telephone , colloquially referred to as a phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other...

 system allowing subscribers to dial trunk calls
Trunking
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...

 without operator
Telephone operator
A telephone operator is either* a person who provides assistance to a telephone caller, usually in the placing of operator assisted telephone calls such as calls from a pay phone, collect calls , calls which are billed to a credit card, station-to-station and person-to-person calls, and certain...

 assistance.

Terminology

As well as the UK, the term "subscriber trunk dialling" is used in other countries such as the Republic of Ireland
Republic of Ireland
Ireland , described as the Republic of Ireland , is a sovereign state in Europe occupying approximately five-sixths of the island of the same name. Its capital is Dublin. Ireland, which had a population of 4.58 million in 2011, is a constitutional republic governed as a parliamentary democracy,...

, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 and India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

. The corresponding term in the USA and Canada
North American Numbering Plan
The North American Numbering Plan is an integrated telephone numbering plan administered by Neustar which encompasses 24 countries and territories, including the United States and its territories, Canada, Bermuda, and 16 nations of the Caribbean...

 is direct distance dialling
Direct distance dialing
Direct distance dialing or direct dial is a telecommunications term for a network-provided service feature in which a call originator may, without operator assistance, call any other user outside the local calling area. DDD requires more digits in the number dialed than are required for calling...

.

The term was extended when, on 8 March 1963, subscribers in London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

 were able to directly dial Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...

 using international subscriber trunk dialling.

Explanation

The introduction in the UK of subscriber dialling of long distance calls removed the distinction that had existed between Trunk and Toll
Trunk vs Toll
In the US, under the purview of the Bell System, local telephone calls were flat rate; i.e., included in the subscribers' fixed fees except in a few big cities, and the term toll was adoptedfor long distance calls because they were subject to tolls....

 calls. This term however, is still widely prevalent in India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

 to describe any national call made other than one's local unit. A "subscriber" is someone who subscribes to, i.e. rents, a telephone line and a "trunk call" is one made over a trunk line
Trunking
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...

, i.e. a telephone line connecting two exchanges a long distance apart. Now that all calls may be dialled direct, the term has fallen into disuse.

History

In the UK, STD started on 5 December 1958 when the Queen
Elizabeth II of the United Kingdom
Elizabeth II is the constitutional monarch of 16 sovereign states known as the Commonwealth realms: the United Kingdom, Canada, Australia, New Zealand, Jamaica, Barbados, the Bahamas, Grenada, Papua New Guinea, the Solomon Islands, Tuvalu, Saint Lucia, Saint Vincent and the Grenadines, Belize,...

, who was in Bristol
Bristol
Bristol is a city, unitary authority area and ceremonial county in South West England, with an estimated population of 433,100 for the unitary authority in 2009, and a surrounding Larger Urban Zone with an estimated 1,070,000 residents in 2007...

, dialled a phone call to Edinburgh
Edinburgh
Edinburgh is the capital city of Scotland, the second largest city in Scotland, and the eighth most populous in the United Kingdom. The City of Edinburgh Council governs one of Scotland's 32 local government council areas. The council area includes urban Edinburgh and a rural area...

 – the furthest distance a call could be directly dialled. The STD system was completed in 1979, though most of the country was covered well before then. The system required that each area have its own STD code which could be dialled by subscribers, and although they are now officially called area codes, it is still common to see and hear the old term in everyday use.

See also

  • List of country calling codes
  • Telephone numbers in India
    Telephone numbers in India
    Country Code: +91 International Call Prefix: 00Trunk Prefix: 0-Fixed numbers:Subscriber Trunk Dialling codes are assigned to each city/town/village, with the larger Metro cities having shorter area codes , the shortest being 2 digits...

  • Trunk prefix
    Trunk prefix
    A trunk prefix is the number to be dialed in a domestic telephone call, preceding any necessary area codes and subscriber numbers. When the number is called from overseas, the trunk prefix is omitted by the caller. In most countries, such as Australia, Germany and the United Kingdom, the trunk...

  • UK telephone numbering plan
    UK telephone numbering plan
    The UK telephone numbering plan, also known as the National Telephone Numbering Plan, is the system used for assigning telephone numbers in the United Kingdom and the Crown Dependencies...


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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