- Subscriber trunk dialling
Subscriber trunk dialling (STD, also known as subscriber toll dialling) is a term for the UK
telephone system allowing subscribers to dial trunk calls without operator assistance.Terminology
The term "subscriber trunk dialling" is used in other countries such as the
Republic of Ireland andAustralia , but the corresponding term in the US and Canada isdirect distance dialing .The term was extended, when on
8 March 1963 ,London subscribers were able to dialParis direct using international subscriber trunk dialling.In
India the term still applies and to dial out of one's unit area, the relevant city code has to be prefixed to the local number. This prefix starts with a 0. Certain numbers are also prefixed with 95 which are local calls within State limits.Explanation
The introduction in the UK of subscriber dialling of long distance calls removed the distinction that had existed between Trunk and Toll calls. This term however, is still widely prevalent in
India 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, 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 when, on
5 December 1958 , the Queen, who was inBristol , dialled a phone call toEdinburgh , the furthest distance a call could be directly dialled at the time cite web
url=http://www.btplc.com/Thegroup/BTsHistory/1912to1968/1958.htm
title=Events in Telecommunications History: 1958, 'BT's history', btplc.com/
date=2008-06-18
accessdate=2008-08-12 ] .However, it was not until1979 cite web
url=http://www.btplc.com/Thegroup/BTsHistory/1969to1980/1979.htm
title=Events in Telecommunications History: 1979, 'BT's history', btplc.com/
date=2008-06-18
accessdate=2008-08-12 ] that the STD system was completed, 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
*
UK telephone numbering plan
*List of country calling codes
*Trunk prefix References
External links
* [http://www.btplc.com/thegroup/BTsHistory/Eventsintelecommunicationshistory/Eventsintelecommunicationshistory.htm The archives of BT including archives of its predecessor organizations] : A good source of information relating to the history of the telephone system in the UK.
* [http://news.bbc.co.uk/onthisday/hi/dates/stories/may/21/newsid_2510000/2510289.stm Archive news article from the BBC on the introduction of Subscriber Trunk Dialling.]
Wikimedia Foundation. 2010.