Dan Popescu wrote:
> I wanna ask you a question if that's OK. First I should tell you that
> I live in Europe. It's not clear to me: when you make an interstate
> call within the US is it necessary to dial 1 before the area code and
> number or can you dial just area code + number?
> [TELECOM Digest Editor's Note: The general rule is we have to dial
> '1' between any two area codes in any of those places.
Not necessarily. Rules vary from place to place depending on legacy
dialing procedures and contemporary needs. Some places need to dial
only seven digits even when crossing an area code boundary. Other
places must dial ten digits even within their own area code. It's
I believe today's system is set up so that you can dial 1+area
code+7digits regardless of where you're calling and if the area code
is needed or not.
My region, for example, has 10 digit dialing. If I call a different
area code (overlay or adjacent) within my region, whether it is a toll
call or not, I do not need the "1". If I go outside the region I do
need the 1.
There's a artificially defined border known as the LATA, which
separates local from toll calls; that is, calls handled by the local
telephone company vs. calls handled by a "long distance" company.
Anyway, some area codes span multiple LATAs. That is, one can dial
only seven digits yet be charged for a long distance call. Other area
codes are very small or even overlays for the same region.
The above mess is a result of (1) divesture of long distance from the
once central Bell System, and (2) competition in local phone service
resulting in an explosion of exchanges which in turn required many new
In the old days, the "1" was not universal. Area codes originally had
a middle digit of only 1 or 0 and exchanges did not have a 1 or 0 as
the middle digit. By this standard the switchgear could distinguish
the type of call.
The "1" prefix was used for two reasons: 1) to serve as a toll alert.
In my area, making a toll call within the same area code required a 1,
that is, 1+7 digits. 2) To serve as a long distance signal to the
switchgear. While the switchgear didn't actually need the 1, having
it made circuitry simpler for some exchanges. (Some places used other
codes). As mentioned, not all places required the 1, you just dialed
the ten digits.
There is also the 0 prefix (0+ac+7d) which is used to signify operator
assistance, such as for collect, 3rd party billing, person to person,
time and charges, credit card.
The concept of a "toll alert" is somewhat obsolete because of the
great variety of billing plans. I have national unlimited, so
theorectically I don't need the 1 at all. But obviously some people
have a la carte plans.