E.123

E.123 - ITU-T committee recommendation defining a submission form for national and international phone numbers , email addresses, and web addresses in printed materials, letterheads , etc.

Content

Format Examples

National phone number, open numbering plan	(033221) 123456
National Phone Number, Fixed Length Numbering Plan	022 1234 5678
International number, in E.123 format	+44 33221 123456 +33 22 1234 5678
E-mail address	name@example.com
Web address	www.example.com

Phone numbers

In the international telephone number format, the leading plus sign (+) indicates the international call prefix, followed immediately by the country code. When making a call, the caller or telephone system must replace the “+” symbol with the international call prefix used in the area from where the call is made.

The brackets are used in the national format to indicate the part of the number, which in some cases may not be used for calling in open numbering plans (numbering plans with a variable number length). In accordance with the standard, the use of brackets in the international format is not allowed due to the fact that for international calls, a numbering plan with a fixed number length is used.

E.123 recommends the following characters to group numbers:

In the national format, only spaces should be used for the visual separation of groups of numbers, "unless the use of other agreed characters (such as a hyphen) is necessary for official purposes."
In the international format, only spaces should be used to visually separate groups of numbers.
The country code, area code and local number must be separated by spaces.

The rules for grouping numbers must comply with established national requirements.

In the national format, the trunk prefix can be included in the area code if necessary based on national requirements. This practice is accepted in most European countries regardless of whether an open or closed numbering plan is used, while in the USA and Canada only the area code is marked as optional.

The tilde (~) indicates that the caller must wait for the “station answer” acoustic signal (continuous beep) while dialing.

A forward slash (/), separated by spaces on both sides, can be used to indicate alternative endings for a number (for example, “555 1234/4444” means 555 1234 or 555 4444).

The local telephone exchange number, dialed in tone mode after dialing the main number, should be located after the main number and separated from it by the words “extension” or “add.” In the national language.

If the PBX provides the DID service, the extension number should be placed immediately after the main number without the use of special characters. If it is necessary to indicate the possibility of dialing various extension numbers, after the main number, a sequence of points in an amount corresponding to the number of digits of the additional number can be used.

Microsoft Canonical Phone Number Format

The canonical telephone number format ^[1] ^[2] from Microsoft is derived from the international E.123 format and allows explicit allocation of the area code using brackets. This format is used in TAPI ( Windows Operating System API for fax modems, modems, and other equipment using dial-up lines). Depending on the user's current location, the dial - up component of the operating system applies one or another set of rules for converting numbers from the canonical format to a format that can be used for calling in the local communication network . These rules may include variable-length codes for a zone, prefixes of long-distance and international calls, as well as access codes for automatic telephone exchanges and sequences for tone dialing of numbers and / or access codes of prepaid calling cards.

This approach allows you to use the phone numbers stored in the user's phone book, regardless of geographic location or carrier . ^[3]

Call sequences may include telephone number digits, tone dialing codes, formatting characters (space, period, and hyphen ) and control characters for AT commands .

Emergency contacts

In May 2008, the Recommendation was supplemented by a separate article defining a standardized, language-independent way of indicating the next of kin or other persons to call in emergency situations in the mobile phone book . ^[four]

It is proposed to indicate these contacts in the phone book with a special format for the “Name” field: 0 nX , where n is a number from 1 to 9, and X semantic descriptive set of letters (for example, “spouse” or “home number”).

The “Number” field of such contacts should contain the actual telephone number of the contact person.

The proposed scheme is a language-independent version of the ICE ( In Case of Emergency ) scheme, which has been distributed in some regions of the world since 2005. ^[five]

Notes

↑ MSDN: TAPI Applications - Device Control - Canonical Address
↑ Microsoft Technet: Dialing Rules and Canonical Address Format .
↑ MSDN: TAPI Applications - Device Control - Storing Phone Numbers in Electronic Address Book .
↑ The ITU standard allows rescuers to establish contact with the victim’s relatives (neopr.) . ITU-T Newslog . International Telecommunication Union (May 20, 2008). Archived on October 19, 2016.
↑ Bob's idea has global impact (Cambridge Evening News) Archived February 3, 2009 on Wayback Machine .

Links

ITU-T. E.123 Recommendation on the ITU website .

[MSDN_TAPI_Canonical_Address-1] MSDN: TAPI Applications - Device Control - Canonical Address

[TechNet_Canonical_Address-2] Microsoft Technet: Dialing Rules and Canonical Address Format .

[MSDN_TAPI_Storing_Address-3] MSDN: TAPI Applications - Device Control - Storing Phone Numbers in Electronic Address Book .

[4] The ITU standard allows rescuers to establish contact with the victim’s relatives (neopr.) . ITU-T Newslog . International Telecommunication Union (May 20, 2008). Archived on October 19, 2016.

[5] Bob's idea has global impact (Cambridge Evening News) Archived February 3, 2009 on Wayback Machine .