Ross Hunter <xhunter@...>
I sent your question to a college radio friend who used to work for Illinois Bell. Here's his reply. Does that answer the question?
I had to dig back quite a way to get an answer for you - and it may only
have applied in Illinois. In the very early 70s (and before), a few tiny
communities in Illinois were served by what was called "community dial
service". These were all small, rural towns. The central office (CO)13 served
either 1 or a group of small communities. The CO had only 1 office code.
Sorry - there is an Area Code (NPA), a central office code (NXX) and the 4
digit individual number associated with each telephone number. This was true
then as well as now. Since the CO had only 1 NXX, it was easy to have LOCAL
CALLING (from one number to another in the same CO) be the last 4 digits of
the telephone number. This is how today's Centrex systems work. If the CO
has 2 NXXs, this was no longer possible since each NXX could have the same
last 4 digits and create code conflicts. In the community dial service, if
you wanted to make a call outside of your home CO, either to another CO in
your NPA or a long distance call, you had to dial an access code to inform
the switch you were not making a local call. Usually, the access code was
"9", just like making an outside call from many of today's company business
Given the fact that an access code was required to go outside the CO, and
the fact that at that time touch tone was NOT widely used so that eliminated
the # and * as an access code, "9" was the choice, at least in Illinois.
That meant that the CO had a maximum capacity of 9000 numbers to be used for
subscribers. Using 9 as an access code eliminated 1000 usable numbers from
When calling into the community dial service, the outside party, if in the
same NPA dialed the full 7 digit telephone number. Callers from a different
NPA dialed 10 digits. The 4 digit calling ONLY applied to calls within the
local community dial CO. Hence that person's problem if he only gave the LD
operator 7 digits (most likely the NPA and the last 4 digits).
That is the way it worked in Illinois. It could have been a different setup
in Orange, but I would suspect it would have to have been similar.