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?
The 1 prefix in the NANPA countries is equivalent to the 0 prefix in most other countries; it prefixes an area code (city code).
The 10 prefix is followed by a company code and the number, to route the call through some other carrier than the phone's default.
The 0 prefix is used as well. Followed by a 10-digit NANPA number, it indicates alternative charging (credit card, third-party billing, etc.) and/or "operator assistance" within the NANPA. Followed by 1, a country code, and a number in that country, it indicates alternative charging for an international (outside NANPA) call. Followed by 11, a country code, and a number in that country, it indicates direct dialing for an international call.
At one time 0 by itself used to get you the local operator, and 00 got you the default long distance operator. I don't know if these still exist.
What about when calling Canada or other NANPA country -- is the
> country code 1 necessary?
All calls within the NANPA are dialled as local or long distance calls. As seen above, it's impossible to reference country code 1 within the NANPA. Intra-NANPA calls are treated as long-distance calls, even if they are international.
-- Mark --