E.123

Last updated
E.123
Notation for national and international telephone numbers, e-mail addresses and web addresses
StatusIn force
Latest version(02/01)
February 2001
Organization ITU-T
Related standards E.163, E.164
Domain telephony
LicenseFreely available
Website https://www.itu.int/rec/T-REC-E.123

E.123 is an international standard by the standardization union (ITU-T), entitled Notation for national and international telephone numbers, e-mail addresses and web addresses. [1] It provides guidelines for the presentation of telephone numbers, email addresses, and web addresses in print, on letterheads, and similar purposes.

Contents

As described by the ITU, in E.123: "+" is the "International Prefix Symbol" used in a "Telephone number, E.123 international notation".

Example formats

Telephone number, national notation (full number dialing)(0607) 123 4567
Telephone number, E.123 international notation+22 607 123 4567
Email addressexample@example.com
Web address / URL www.example.com

Telephone number

In the international telephone number notation, the leading plus (+) serves as an international prefix symbol, and is immediately followed by the country code. The user or the telephone system should replace the + symbol with international dialing prefix used in the caller's location.

Parentheses are used in national notation to indicate digits that are sometimes not dialed, such as area code in variable-length dialing numbering plans. Parentheses are not allowed in the international notation, according to the standard, as international callers use fixed number dialing.

For digit grouping, E.123 specifically recommends that:

No recommendation is made for grouping rules for digits in the local number, instead some examples of commonly used groupings are shown.

In national notation, the trunk prefix can be included with the area code if required by national writing conventions; trunk prefix is included in most European countries whenever they use fixed or variable dialing, but is omitted in USA and Canada where phone numbers only indicate optional area code.

A tilde (~) indicates an additional dial tone that the user should wait for.

A slash (/) with spaces on either side may be used to indicate alternative ending for numbers (i.e. "555 1234 / 4444" means 555 1234and555 4444).

The non-dialable PBX (private branch exchange) extension number should be separated by words "extension" or "ext." in the national language after the phone number.

When the PBX is capable of direct inward dialing, the extension number should be written directly after the phone number, without using any distinct symbols. If there is a need to indicate in-dialing capability of the telephone number, a number of dots (....) corresponding to the length of the extension number can be added at the end.

Microsoft telephone number format

Microsoft canonical address format for telephone numbers [2] [3] derives from E.123 international notation by allowing explicit indication of area code with parentheses.

The canonical format is used by the Telephony API (TAPI), a Windows programming interface for dial-up fax, modem, and telephone equipment. Depending on the user's current location, the Windows' Dial-Up Networking (DUN) component applies a set of dialing rules to transform the canonical phone number into a locally dialable calling sequence for the modem device. The dialing rules may include variable-length dialing for area code, trunk access and international access prefixes, central office/service access numbers, and calling cards tone numbers. [2] [3]

With this approach, phone numbers stored in the phone book remain unchanged when the user moves to a different geographical location or selects a different phone service provider. [4]

The calling sequence can contain dialable numbers such as digits 0–9 and DTMF tones ABCD*#, formatting characters ␣ . -, and control characters ! P T , W @ $ ? ;, which correspond to the Dial command of the Hayes AT command set.

Emergency contact information

A standardized language-independent way to identify a next-of-kin (or other emergency contact) in a mobile handset’s directory, in case of an emergency, has in May 2008 been adopted as a new clause in Recommendation E.123.

It proposes to store emergency contact numbers prefixed with Arabic numerals in the form “0nxxxx”; “n” is a digit from 1 through 9 and “xxxx” is any meaningful descriptive character string in any language or script (e.g. “Anna” or “Spouse”).

In the handset's directory this would be displayed as "01Anna" or "01Spouse" enabling easy identification by the emergency services. The handset’s directory entry (in the “contact number” field) would contain the actual number of the person to call in case of emergency. [5]

This language-independent recommendation preceded the popular "ICE" (In Case of Emergency) scheme introduced in 2005 to the English-speaking world. [6]

See also

Related Research Articles

A country code is a short alphanumeric identification code for countries and dependent areas. Its primary use is in data processing and communications. Several identification systems have been developed.

The Telephony Application Programming Interface (TAPI) is a Microsoft Windows API, which provides computer telephony integration and enables PCs running Microsoft Windows to use telephone services. Different versions of TAPI are available on different versions of Windows. TAPI allows applications to control telephony functions between a computer and telephone network for data, fax, and voice calls. It includes basic functions, such as dialing, answering, and hanging up a call. It also supports supplementary functions, such as hold, transfer, conference, and call park found in PBX, ISDN, and other telephone systems.

E.164 is an international standard, titled The international public telecommunication numbering plan, that defines a numbering plan for the worldwide public switched telephone network (PSTN) and some other data networks.

<span class="mw-page-title-main">North American Numbering Plan</span> Integrated telephone numbering plan of twenty North American countries

The North American Numbering Plan (NANP) is a telephone numbering plan for twenty-five regions in twenty countries, primarily in North America and the Caribbean. This group is historically known as World Zone 1 and has the telephone country code 1. Some North American countries, most notably Mexico, do not participate in the NANP.

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.

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">Area code 868</span> Trinidad & Tobagos telephone area code under the North American Numbering Plan

The area code 868 is assigned to Trinidad and Tobago, a member of the North American Numbering Plan (NANP). The telephone numbering plan for the country is known as the National Numbering Plan. It is part of a system used for assigning telephone numbers in Trinidad and Tobago, and functions as a part of the North American Numbering Plan (NANP). It is regulated by the Telecommunications Authority of Trinidad and Tobago, which holds responsibility for telecommunications in the country.

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 New Zealand</span> New Zealand numbering plan

The New Zealand telephone numbering plan describes the allocation of telephone numbers in New Zealand and the Pitcairn Islands.

<span class="mw-page-title-main">Telephone numbers in the Philippines</span> Audio telecommunications dialing schemes in the Southeast Asian country

Telephone numbers in the Philippines follow an open telephone numbering plan and an open dial plan. Both plans are regulated by the National Telecommunications Commission, an attached agency under the Department of Information and Communications Technology (DICT).

<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.

All of Finland, including Åland, has the same country code, +358.

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

Telephone numbers in the Republic of China (Taiwan) use a system of area codes, beginning 02 to 08. The leading digit(s) following the area code denote the network operator (Chunghwa Telecom and its competitors). Mobile numbers begin 09. The international code for calls into Taiwan is 886.

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

Thailand's telephone numbering plan in Thailand is managed by the National Broadcasting and Telecommunications Commission (NBTC) in accordance with International Telecommunication Union's (ITU) recommendation E.164.

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 Russia</span>

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.

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

  1. ↑ "E.123 : Notation for national and international telephone numbers, e-mail addresses and web addresses". www.itu.int. Archived from the original on 2019-11-11. Retrieved 2019-11-11.
  2. 1 2 MSDN: TAPI Applications - Device Control - Canonical Address
  3. 1 2 Microsoft Technet: Dialing Rules and Canonical Address Format.
  4. ↑ MSDN: TAPI Applications - Device Control - Storing Phone Numbers in Electronic Address Book.
  5. ↑ "ITU standard allows emergency rescue workers to identify a victim's next-of-kin". ITU-T Newslog. International Telecommunication Union. 20 May 2008. Archived from the original on 19 October 2016. Retrieved 24 May 2008.
  6. ↑ Bob's idea has global impact (Cambridge Evening News) Archived February 3, 2009, at the Wayback Machine
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