Re: Internationalization--Standard Conventions (phone)

From: Markus Kuhn (
Date: Sun May 30 1999 - 06:38:58 EDT

Herbert Elbrecht wrote on 1999-05-30 09:32 UTC:
> Hi, I do it my way:
> fon/fax: ++49+69-722012
> and I think it fits well for the job to be done!

I have seen many of these attempts to improve the ITU standard notation.
For example, "++49 [0]69 722012" is another one that is occasionally

ITU members have done some acceptability tests with random users before
the E.123 recommendation was published. They tried many different more
fancy notations such as those above. It turned out, that - although
these notations often looked much more intuitive to whoever came up with
them - they were not at all more intuitive to those exposed to them,
often they were even more confusing. So ITU stayed with one of the
simplest proposals that was made, i.e. just adding a single plus to
indicate that this is the international notation.

Actually, the full E.123 notation for use on letterheads where
sufficient space is available looks like this (ISO's number as printed
in the ISO catalogue):

            national (022) 7490111
Telephone -----------------------------
            international +41 22 7490111

The combination of providing both a national and international number
was the most self-explanatory notation in the usability tests. However,
people are today so familiar with the international notation already
that few use the full notation and most people only apply the compact
international format alone. E.123 also allows using "Telephone +41 22
7490111" alone. The notation is explained by the way in the telephone
books of a number of countries, therefore it is even more advisable to
stay with the standard to avoid confusion.

To come back to Unicode: The U+2315 TELEPHONE RECORDER sign is defined
in ITU-T Recommendation E.123 as well, in case somebody ever asks for a
reference here.


Markus G. Kuhn, Computer Laboratory, University of Cambridge, UK
Email: mkuhn at,  WWW: <>

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