[comp.dcom.telecom] introduction of N[01]X prefixes

cmoore@BRL.ARPA (VLD/VMB) (07/20/88)

We have just had a note in this Digest regarding the forgetting of
leading 1+ for long-distance from 312 area (Chicago etc.).
An old note from me pointed out that the first N0X/N1X prefix in
New York City back in 1980 was 409, which was then unused as area
code.  I have now just seen a Washington (D.C.) Post article (Nov.
6, 1987, page F1) about the new 1+ requirement in that area, and
it said that 917 (also an unused area code) was coming as a prefix
in the Rockville area (in nearby Maryland).  What were the early
N0X/N1X prefixes in the Chicago area?