[asterisk-users] Zip code, city and area codes

[Joe Greco]

> If you need something more than that, it will be difficult.  A zip code can serve multiple NPA-NXX's
> and an NPA-NXX can be in multiple zip codes.

Don't forget that number portability significantly muddied the waters, and
VoIP has created an environment where there's no longer any need for a
physical relationship.  For example, ipKall offers Washington state phone
numbers for free.  Probably unusual to find your average end user having 
such a number, but some people on this list will.

Number portability probably means that you either need a bit of fuzzy logic
to determine if the ZIP and the NPA-NXX are in the same region, or you need
to be clever about the implementation and how you handle negative matches.

... JG
-- 
Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net
"We call it the 'one bite at the apple' rule. Give me one chance [and] then I
won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN)
With 24 million small businesses in the US alone, that's way too many apples.