I do disagree that it takes much research, though, to determine
> one's local calling area, at least in California and a few other
> states that I am familiar with that have all local office codes that
> are local clearly listed in the front of the phone book.
My local telephone directory requires 12 (twelve) pages of charts to describe the various local calling areas. Clear? I don't think so.
Helping to muddy the waters is that the exchange named refers to the principal town center where the exchange is physically located. However, in suburban areas the municipality name, post office name, and generally used name are all different. Thus the exchange may be listed as in A-Village, but will also include parts of X township and Y township. The next town, B-Village, will have the other parts of Y Township and Z Township.
Again, back in the day when a suburban telephone exchange hosted one or maybe two NNXs this wasn't a problem. My town had ONE exchange, now it has 20 (TWENTY).
[TELECOM Digest Editor's Note: Same thing here. For how many ever centuries, we got along just fine with 620-EDison and its newer variation, 620-331. That was for everything and everyone. And it still _mostly_ is that way. 630-330 and 620-332 were special cases; 330 was a few centrex setups around town, a lot of celllar phones, including my own, etc. 332 was city government and cell phones. Then Mercy Hospital's centrex started making outgoing calls on 620-332-2xxx as well as some other centrexes around town. But now lately I am seeing bunches of cell phones in 620-719 and 620-779 and 630-924. It is getting harder to keep track of all the prefixes used, same as the huge number of area codes. PAT]