On Apr 6, 12:15*pm, Stephen Sprunk wrote:

Ah, so they weren't really area codes per se. *Mexico never intended to
be part of the NANP; we just had dialing shortcuts for commonly-called
areas within Mexico.
Did using those shortcuts result in lower rates since an operator wasn't
needed? *Or was it just a matter of convenience/speed?

It depends if there were any discounts for directly dialed
international calls at that time. I don't know when such discounts
began, but probably later since it took time to get IDDD capability
installed.

When discounts began for domestic direct dialed calls (circa 1971)
they weren't too much--as time went on the difference became greater.
In the 1970s, if a subscriber didn't have DDD capability or was having
trouble placing the call, they still got the cheaper DDD rate for a
plain station call. Later on they charged dearly for any operator
assistance, even if there was line trouble.