Telecommunications technology and telephone numbering system
For a North American equivalent, see Direct distance dialing.
This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Subscriber trunk dialling" – news · newspapers · books · scholar · JSTOR(December 2011) (Learn how and when to remove this message)
Subscriber trunk dialling (STD), also known as subscriber toll dialing, is a telephone numbering plan feature and telecommunications technology in the United Kingdom and various Commonwealth countries for the dialling of trunk calls by telephone subscribers without the assistance of switchboard operators.
Switching systems to enable automatic dialling of long distance calls by subscribers were introduced in the United Kingdom on 5 December 1958. The system used area codes that were based on the letters in a town's name. A ceremonial first call was made by Queen Elizabeth II from Bristol to Edinburgh.[1]
A similar service, built on crossbar equipment, using regionally structured numbering, rather than alphanumeric codes, was experimentally introduced by P&T in Ireland in 1957, with the first services being in Athlone. A full service was rolled out in 1958, initially to exchanges in Cork and then Dublin and its hinterland, and gradually to all areas with automatic exchanges.[2]
The term 'STD call' was once commonly used in the UK, Ireland, Australia, India, and parts of Southeast Asia, but it may be considered archaic today, or possibly even no longer be understood. Other less technical terms like 'national calling,' 'long distance calling' and so on are now more commonly used. The distinction between local and long distance / STD calls is also no longer relevant to many users, as calls are charged at flat or bundled rates. It is also necessary to dial area codes on some calls, especially from mobile phones, so they are considered part of the number.
Terms such as 'area code', 'prefix' or 'national dialling code' tend to be used in place of 'STD code' in the UK and in Ireland.
^"International Subscriber Trunk Dialling introduced". The Telegraph. 10 March 2017. Archived from the original on 11 March 2017.
^"Committee on Finance. - Vote 55—Posts and Telegraphs. – Dáil Éireann (16th Dáil) – Wednesday, 15 Jul 1959 – Houses of the Oireachtas".
and 28 Related for: Subscriber trunk dialling information
Subscribertrunkdialling (STD), also known as subscriber toll dialing, is a telephone numbering plan feature and telecommunications technology in the...
direct dialing (IDD) or international subscriberdialling (ISD) is placing an international telephone call, dialed directly by a telephone subscriber, rather...
article. 0 was traditionally the number dialled for the operator for long-distance calls before subscribertrunkdialling (STD) was introduced, and so was retained...
dialling of a single or two-digit national trunk prefix preceding any area codes and the destination subscriber number. In most countries, the trunk prefix...
introduction of subscribertrunkdialling (STD). In the UK, local as well as long-distance telephone calls were chargeable to the caller and the term trunk calling...
the trunk line operator requested in pre-subscribertrunkdialling telephone systems by a subscriber calling the local operator (British usage) Trunk (disambiguation)...
were first known as subscribertrunkdialling (STD) codes. Depending on local dialing plans, they are often necessary only when dialed from outside the code...
non-geographic codes. Historically, like the UK, the term STD code (SubscriberTrunkDialling) was used. However, the terminology is archaic and is no longer...
020 is the national dialling code for London in the United Kingdom. All subscriber numbers within the area code consist of eight digits and it has capacity...
India by the International Telecommunication Union in the 1960s. Subscribertrunkdialling (STD) codes are assigned to each city, town and village. These...
need to automate telephone dialling resulted in every exchange being allocated either a unique SubscriberTrunkDialling (STD) code or unique range of...
of subscriberdialed calls, numbering patterns were reassigned to provide for mnemonic methods of improving customer performance. Subscribertrunk dialling...
of the United Kingdom had no lettered telephone dials until the introduction of SubscriberTrunkDialing (STD) in 1958. Until then, only the director areas...
two-letter code after the initial zero to form the first part of the subscribertrunkdialling code for a region. For example, Aylesbury was assigned 0AY6, which...
allow for the expansion of the subscriber base as technology has improved. The introduction of subscribertrunkdialling was slow, partly because of the...
service to direct distance dialing is subscribertrunkdialing (STD), and ISD for international subscribertrunkdialing.[citation needed] Queen Elizabeth...
Kingdom, the "area code" is often referred to as a "subscribertrunkdialling code" (STD code) or a "dialling code". STD codes are two, three, four or, exceptionally...
the initial '0' is a trunk prefix that is not required when dialling from abroad. Redditch is one of a small number of dialling codes which still retains...
three parts, the trunk prefix code (0 in the UK), an STD code (area code) followed by a local number. The STD (SubscriberTrunkDialling) code indicates...
summer 1972. By the early 1960s, following the introduction of SubscriberTrunkDialling, the number of possible exchange name permutations were running...
calling code of Bangladesh is +880. The dial plan type in Bangladesh is closed, and "0" is the Trunk prefix. When dialling a Bangladesh number from inside Bangladesh...
trunk access code 0 must be dialled before the telephone number, extending the dialling sequence to 10 digits. If dialling from overseas, the 0 (Zero)...
group switching centres became important with the introduction of subscribertrunkdialling (STD) in 1958, initially from Bristol central telephone exchange...
Standard Test Condition, a measurement standard for PV solar panels SubscriberTrunkDialling, a telephone numbering plan feature and telecommunications technology...
subscriber number. No trunk prefix is used. The following are area codes and operator prefixes in Uzbekistan: International call prefix when dialling...