[mod.telecom] prefix duplication in newly-split area code

cmoore@BRL.ARPA (Carl Moore, VLD/VMB) (01/01/86)

When a new area code is created, how long does it take before any prefix
is duplicated between the new area code and what's left of the one that
was split?  For example, if you look up addresses with phone #'s in
New York City, you can go on quite a while with the list of 212-area-
before-creation-of-718 prefixes.