The Illinoix Commerce Commission doesn't assign central office codes. Neustar's NANPA does. Since overlays with mandatory 1+ ten-digit dialing exists in New York City, then it is quite possible that NANPA might ultimately assign a 212-212 code, as well as a 646-646 code,
718-718 code, and so forth. At present, there are no such codes assigned within New York City, where the numerics of the office code duplicate their own area code. So the lowest theoretical number in the NANP, counting dialpulses, would still be 212-212-1111. Note that the N11 codes are not assignable as Area Codes nor as "real" office codes within an area code, thus you can NOT have 211+NXX nor NPA+211 at present as real area+office codes.Actually, the highest theoretical dialpulse-counted NANP number would be 900-900-0000. At present, there is no service provider who is assigned the premium-rate 900-900 code, but that code is also not restricted from possible future assignment by Neustar. And at > There _is_ an 'area code 200', or more precisely it is a special
This use of 200 followed by seven-digits is NOT an area code no matter how you want to describe it. It is strictly a plant test type of code and has no universal application as such. Most central offices in the US and Canada have some kind of "ring back" test dialing procedure, and while there are "patterns" that can be seen, there is NO uniformity at all.
Your one-time Chicago use of 1+200 followed by seven-digits is just that, a one-time Chicago "only" use of 200 as a plant test code for that function.
Other areas used a three-digit "NXX" type of a code followed by the last four-digits, not the full seven-digits, for "ring back" purposes.
It is also possible that many parts of the NANP have used 200 as a plant test code at one time or another for other test purposes, other than "ring back", such as ANAC, reaching the test board, reverse battery purposes, and so forth. Just because your one-time use in Chicago of 200 for "ring back" does NOT qualify that function as a universally recognized "area code".
As an "area code" in the NANP, at present, 200 is universally known to be "unassigned" by Neustar, just as it was universally known to be "unassigned" by Bellcore and before that "unassigned" by AT&T. It is "earmarked" for some future "special services AREA code" in the NANP, in the way that "special AREA code" 900 is premium rate, "special AREA code" 800 and now 888, 877, 866, etc. when used as an AREA code in a ten-digit number is for toll-free, etc.
Thus, Bob Goudreau is correct when he stated a few days ago that if NANPA were to ever put area code 200 into service, i.e. 200 as a real universally recognized "special services" area code, which would NOT be a locally used plant test function in some places, then
200-200-0000 could be the lowest theoretical telephone number in the NANP when looked at on a purely "numerical" basis. And for that matter, theoretically, 200-200-0000 *IS* the lowest possible theoretic numeric number in the NANP, although at present, SAC 200 is unassigned but reserved for a future NANP-wide undefined special function along the lines of premium rate 900, toll free 800/etc., personal numbering 500, etc., and the next triplet of '200' is a theoretical office code yet to be assigned within that future to be assigned SAC 200. But of course, this is all theoretical at present.