Trunk prefix

Last updated

A trunk prefix is a digit sequence to be dialled before a telephone number to initiate a telephone call for the purpose of selecting an appropriate telecommunications circuit by which the call is to be routed.

Contents

Making a domestic (national) telephone call usually requires the 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 is 0.

For international telephone calls, the national trunk prefix is not dialled; instead, an international trunk prefix (or "+") is typically required, followed by the destination's country code.

Example

This example assumes that a call is to be made to a customer in the Australian state of Queensland with the local number 3333 3333 and the area code 7.

A caller from outside Australia must dial the international call prefix of the originating country and the country code (61 for Australia), then the area code (7), and then the local subscriber number. Therefore, a caller in the UK must dial 00 61 7 3333 3333, while a caller in the US must dial 011 61 7 3333 3333.

Calling inter-area (within Australia) (e.g. from Western Australia with area code 8), a caller need not dial an international trunk prefix or a country code. Instead, the caller must at least dial the Australian trunk prefix (0) followed by the area code (7) and then the local subscriber number: 07 3333 3333. Calling from within the Queensland (7) area, a caller need only dial the telephone number: 3333 3333.

However, since the early 21st century, the majority of telephone systems worldwide can recognise the area of origin of the call, its direction and destination to facilitate communication faster. If the full international number is used, then this full international number may be dialled from nearly any telephone within a recognisable landline or mobile network. This has become particularly vital for users of mobile phones.

When conducting business, e.g., for display on business cards or stationery, a telephone number is represented as +61 7 3333 3333, and includes only the digits that must be dialled internationally. The plus sign indicates that an international trunk prefix is first dialled and, therefore, a country code follows.

Countries using national trunk prefixes

Countries that use 0 as national trunk prefix

Africa

South America

Asia

Europe

Oceania

Countries that use 8 as national trunk prefix

Countries that use other trunk prefixes

The number next to a country denotes its national trunk prefix.

Countries that no longer use a national trunk prefix

See also

Related Research Articles

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.

A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, reachable by a system of destination code routing. Telephone numbering plans are defined in each of the administrative regions of the public switched telephone network (PSTN) and in private telephone networks.

<span class="mw-page-title-main">Telephone numbers in Australia</span>

The Australian telephone numbering plan governs the allocation of telephone numbers in Australia. It has changed many times, the most recent major reorganisation by the Australian Communications and Media Authority taking place between 1994 and 1998.

International direct dialing (IDD) or international subscriber dialling (ISD) is placing an international telephone call, dialed directly by a telephone subscriber, rather than by a telephone operator. Subscriber dialing of international calls typically requires an international call prefix to be dialed before the country code.

In Argentina, area codes are two, three, or four digits long. Local customer numbers are six to eight digits long. The total number of digits is ten, for example, phone number (11) 1234-5678 for Buenos Aires is made up of a 2-digit area code number and an 8-digit subscriber's number, while (383) 123-4567 would be an example of a Catamarca number.

<span class="mw-page-title-main">Telephone numbers in the Republic of Ireland</span>

Numbers on the Irish telephone numbering plan are regulated and assigned to operators by ComReg.

<span class="mw-page-title-main">Telephone numbers in Cyprus</span> Telephone guide to Cyprus closed telephoning numbering plan.

Telephone numbers in Cyprus follow a closed telephone numbering plan which was adopted on 1 December 2001. As a result, for landline phone numbers the digit 2 followed by the old area code was affixed to the subscriber number and for mobile phones 9 was affixed to the phone number. The plan is also used in Akrotiri and Dhekelia.

Area code 246 is the telephone area code in the North American Numbering Plan (NANP) for Barbados. The sequence 246 spells BIM on an alpha-numeric telephone keypad, a nickname for the island.

Widespread UK telephone code misconceptions, in particular brought on by the Big Number Change in 2000, have been reported by regulator Ofcom since publication of a report it commissioned in 2004.

<span class="mw-page-title-main">Telephone numbers in Romania</span>

The dialling plan for mobile networks and new landline operators is closed; all subscriber numbers must be dialled in full. For landline numbers starting with 02, the dialling plan used to be open; the trunk digit and area code could be omitted if the caller was in the same area code as the callee. However, starting May 3, 2008, all landline numbers must be dialled in full.

The Brazilian telephone numbering plan uses a two-digit area code plus eight-digit local phone numbers for landlines and nine digits for mobile lines. Public utility services use short phone numbers, always starting with 1.

Telephone numbers in Switzerland are defined and assigned according to the Swiss telephone numbering plan administered by the Swiss Federal Office of Communications. The plan has been changed several times and the most recent reorganization was implemented in March 2002.

Telephone numbers in Oceania use a variety of area codes to denote their location along with their own area code depending on the country's geographic makeup. They also have other prefixes to denote different types of mobile services and international calls. There are exceptions because of regional variations and time zones. 

<span class="mw-page-title-main">Telephone numbers in Italy</span>

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 Bulgaria are under a full number dialing plan, meaning that the full national number must be dialed for all calls, while it retains the trunk code, '0', for all national dialling. Area codes are prefixed with a trunk code of 0 only when dialled domestically.

<span class="mw-page-title-main">Telephone numbers in Pakistan</span>

Telephone numbers in Pakistan are ten digits long. Landline numbers and mobile numbers have different structures. Geographically fixed landline are prefixed by an area code which varies in length depending on the significance of the place. Mobile numbers are prefixed (03) followed by a two-digit code indicating the telephone operator. The international country code for Pakistan is '+92'.

Telephone numbers in Canada follow the fixed-length format of the North American Numbering Plan (NANP) of a three-digit area code, a three-digit central office code, and a four-digit station or line code. This is represented as NPA NXX XXXX.

<span class="mw-page-title-main">Telephone numbers in Belgium</span>

A telephone number in Belgium is a sequence of nine or ten digits dialed on a telephone to make a call on the Belgian telephone network. Belgium is under a full number dialing plan, meaning that the full national number must be dialed for all calls, while it retains the trunk code, '0', for all national dialling.

National conventions for writing telephone numbers vary by country. The International Telecommunication Union (ITU) publishes a recommendation entitled Notation for national and international telephone numbers, e-mail addresses and Web addresses. Recommendation E.123 specifies the format of telephone numbers assigned to telephones and similar communication endpoints in national telephone numbering plans.

<span class="mw-page-title-main">Telephone number</span> Sequence of digits assigned to a telephone subscription

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.

References