Is there an official number for the standard named "ISO Basic Latin Alphabet"?

There is many references to a standard 26 letters alphabet named "ISO basic latin alphabet" (aka plain english alphabet). The name include "ISO", but I'm not able to find an official ISO standard number attached to it.

The "ISO/IEC 646" often mentionned, contains more than 26 chracters and is used specificly to associate characters to numbers for the computer industry.

I'm looking for an ISO standard that specify only the 26 characters used as "basic latin alphabet".

Solution

ISO and IEC have a Joint Technical Committee, JTC 1, whose Subcommittee 2 (SC 2) is responsible for coded character sets. The standards this subcommittee is responsible for include the following:

ISO/IEC 646:1991: this is the 7-bit coded character set that includes the "ISO basic Latin alphabet" but also includes numbers, punctuation marks and a few other; see also ISO/IEC 646 on Wikipedia.
ISO/IEC 8859-1:1998: Information technology -- 8-bit single-byte coded graphic character sets -- Part 1: Latin alphabet No. 1. This is part of a multi-part standard; other parts are geared towards specific geographic regions or languages, e.g. ISO/IEC_8859-2 for Central and Eastern Europe.
ISO/IEC 10646:2017: Information technology -- Universal Coded Character Set (UCS): a standard that supports the representation of the written form of most languages of the world that have a writing system (and also of a number of ancient languages).

Even 7-bit ASCII covered more than just the letters of the ISO basic Latin alphabet because the standards listed here were created for the purpose of enabling information exchange, and a standard that covered just the letters, i.e. excluding numbers, punctuation marks and some basic control characters, would have been insufficient.

Also check Western Latin character sets (computing): all the standards listed there (both official and proprietory) go beyond the letters of the Latin alphabet.