cmoore@brl.mil (VLD/VMB) (11/06/90)
Based on what I came across years ago, I do NOT think that 513 and 606 are interchangeable in any circumstances. (These are the area codes for Cincinnati and the neighboring part of Kentucky.) There was (still is?) an intercept message saying "We're sorry, but calls to Kentucky cannot be completed using area code 513. You must dial area code 606." This cut down on the number of prefixes available in 513, and could have gone away later if prefix supply ran short in 513.
IZZYAS1@oac.ucla.edu (Andy Jacobson) (11/08/90)
In response to <cmoore@BRL.MIL>: My knowlege of the Cincinatti area code/prefix biz I must admit is limited to notes in the front of the phonebook. The directory listed as I remember at least a couple of prefixes which could be reached from either 513 or 606. These were located "on the map" in both the areas for Ky, and Oh adjacent to the river. These were the only prefixes on the map that were listed to more than one geographical region (by map region number). I remember trying one of the numbers (from the Dayton area) and finding that I did not need the 606 area code to call it (It was a a business in Ky, if I remember) I don't remember how it was listed in the book (as requiring 513, or 606). It may be that what I'm thinking of was a early version of what we now have in the way of 976 numbers that are the same in two area codes. (I see a lot of ads for 976 numbers that are the same in 213 and 818.) As well, it could be more like a "choke" prefix, as many radio stations use. Which are in some cases the same prefixes in adjacent area codes.