Well, if you're going to keep a list of area codes, and reject numbers whose first three digits aren't on that list, why not maintain a list of exchange codes as well? I mean, if you're going to reject '123-456-7890' because '123' isn't a valid area code, shouldn't you also reject '212-555-7890', because '555' isn't a valid exchange code?

Of course, keeping a list of exchanges per area, that still isn't the end. Not all exchanges connect 10000 numbers.

In reply to Re^4: Regular expression for Fax numbers by JavaFan
in thread Regular expression for Fax numbers by dxxd116

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