The answer here is:
GROUP OF SEVEN, usually abbreviated to G7, i.e. the international political forum comprised of Canada, France, Germany, Italy, Japan, the UK, and the USA.
To find this, note first that the listed numbers are all:
valid international dialling codes (i.e. the prefixes you use before the local phone number when calling somebody in another country).
And these relate to:
238 CAPE VERDE
689 FRENCH POLYNESIA
225 IVORY COAST
971 UNITED ARAB EMIRATES
1 UNITED STATES
44 UNITED KINGDOM
Note next that these pairs:
indicate countries which are very close together alphabetically. Armed with the title hint that it's 'not what you see that counts' let's look at the nations that come in between these countries in a list of international dialling codes.
What you draw out of this process really depends on what you consider as your authoritative information source here, but I can identify the following 'inbetweeners':
FRANCE, FRENCH ANTILLES, FRENCH GUIANA
UNITED STATES, UNITED STATES VIRGIN ISLANDS
And by now the intended pattern is clear:
If we take only the most major of all the countries listed above, then we produce the group: CANADA, FRANCE, GERMANY, ITALY, JAPAN, UK, and USA. These are clearly recognisable as the group of nations that make up the Group of Seven (I wonder how they came up with that name?!), which should surely be the 12-letter answer intended here!