[mod.telecom] trivia and transposed digits

cmoore@BRL.ARPA (Carl Moore, VLD/VMB) (12/18/85)

Trivia:
366 prefix in Newark (Delaware, 302 area; and Ohio, 614 area)
658 prefix in Wilmington (Delaware, 302 area; Massachusetts, 617 area)

I can think of 2 cases where transposing a digit lands you in a
ADJOINING exchange.  These may have had letter prefixes at one
time.  How many wrong numbers result from these?  (I've received
wrong-number calls along these lines, but not intended for adjoining
exchange.)
668 Parkville and 686 Essex (301 area, in Baltimore, Md. suburbs)
327 Export and 372 Monroeville (412 area, in Pittsburgh, Pa. suburbs)