The problem of area codes

[kalvado]

An established pattern which helps recognition. 3+3+4 is a phone number, 4+4+4+4 is a credit card, 3+2+4...
Breaking the pattern.. like using comic sans for the text. It certainly can work, but.. 

Note that phone numbers vary according to the country. In France, as mentioned above, is 2+2+2+2+2. In Spain it can be either 3+3+3, 3+2+2+2 or (in a few provinces like Madrid or Barcelona) 2+3+2+2. I despise that last pattern, and try to change it to 3+2+2+2, treating the first digit of the 7 digit subscriber number as part of the prefix like elsewhere.

Sure, there are different standards in different places and different languages. It's not that I need to write down Spanish or Chinese phone numbers too often, though.

[zachary_amaryllis]

Here in (920) area code there is a lawyer ad to call 222-2222, and a competing lawyer ad to call 777-7777.

Taxi services seem to have consumed those numbers, at least, back when there WERE taxis.

Foco had one that was all 2's (with a 970 in front).
Denver had two, one with all 3's, and one with all 7's.

[kphoger]

... or (in a few provinces like Madrid or Barcelona) 2+3+2+2. I despise that last pattern, and try to change it to 3+2+2+2, treating the first digit of the 7 digit subscriber number as part of the prefix like elsewhere.

Sure, there are different standards in different places and different languages. It's not that I need to write down Spanish or Chinese phone numbers too often, though.

Mexico is an interesting case.  Its area codes are geographically based.  Almost all area codes are (AAA) NNNNNNN, but its three largest cities are (AA) NNNNNNNN instead.

Therefore, most of the country writes its phone numbers as (AAA) NNN-NNNN.  But in those three cities, it's common to find both (AA) NNNN-NNNN and (AA) NN-NN-NN-NN.

However, those three cities' area codes still fit within the geographical framework.  This means that, even though nobody seems to actually do so, it's possible to conceptualize each of them as an overlay of multiple area codes—all of which have the same first two digits.  So, for example, with metro Monterrey:

(81) 4982-6610
(81) 2599-3004
(81) 7827-6566

... is functionally the same as ...

(814) 982-6610
(812) 599-3004
(817) 827-6566

... if you imagine that the 814, 812, and 817 area codes are all overlain with each other.  They all even fit squarely within the '8' region.