E.123

Recommendation E.123 of the International Telecommunication Union contains design rules for national and international telephone numbers , e-mail addresses and web addresses in printed matter and business correspondence.

example

Telephone, international	[phone]
Telephone, national	[phone]
e-mail	[e-mail]
Web address / url	www.example.com

National numbers

In the case of national numbers, components are bracketed that are not always dialed:

[phone]

International numbers

Notation

• The E.123 recommends the plus sign ("+") to identify country codes .
• The number components country code, area code and subscriber number are separated by spaces.
• If necessary, the participant number can be subdivided with additional spaces for better readability.
• The distance between the area code and subscriber number should be greater than the other spaces.
• For companies with a telephone system , the extension numbers are not separated by a space.

example

[phone]	Standard: Separation of the country code, area code and subscriber number
[phone]	Company with telephone system (head office)
[phone]	with extension number
[phone]	Participant number with additional spaces

Number entry

The phone number is entered unchanged on mobile phones:	[phone]
On landline telephones (in all EU countries and many others) the "+" is replaced by two zeros :	004989123456

Emergency numbers

In May 2008, the E.123 was supplemented by a procedure to mark emergency numbers in the address book of a mobile phone . Numbers of people who should be notified in an emergency are saved with prefixed Arabic numerals in the form "0nxxxx". n stands for a number from 1 to 9 and xxxx for the name or a descriptive text such as "Anna" or "Spouse":

"01Anna" or "02Ehepartner"

Most phones have entries with numbers at the top of the list, making them easy to identify. The telephone number to be called in an emergency is then stored in the telephone number field of these entries.

In contrast to various private initiatives such as “ICE” ( English : “ In Case of Emergency ”) or “IN” ( German : “ In Emergency ”), the E.123 is a language-independent international standard .

comparison

The E.123 recommendation had a considerable influence on the usual spelling of phone numbers . DIN 5008 has also adopted the plus notation for "telephone numbers in correspondence with foreign countries".

The Microsoft TAPI ( Telephony Application Programming Interface ) notation is based on E.123, but recommended that the area code be put in brackets for its canonical format, i.e. plus notation with the first bracket after the country code. This spelling then also appeared frequently in correspondence. Other extensions, such as the separation of the ISDN subaddress , also originate here.

The IETF RFC3966 "The tel URI for Telephone Numbers" refers to the fact that the spaces of the E.123 may not be used. Instead, only the four permitted separators dot, dash and brackets [.- ()] can be used to subdivide the phone number.

See also

• DIN 5008
• E.164
• Phone number

Web links

• Original ITU-T recommendation E.123

Individual evidence

1. ↑ Recommendation E.123 (2001) Amendment 1 (05/08)
2. ↑ ITU standard allows emergency rescue workers to identify a victim's next-of-kin ( Memento of the original from October 19, 2016 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.