What does a phone number in the following format indicate?

Phone numbers in the US have the following format.

(XXX) YYY-ZZZZ

I have received text messages from numbers that are 1YY. Normally you will never see a 1 as the first digit of the exchange. I believe that these are internal numbers used by the phone company. Can anyone confirm that or tell me what the number means?

Try going to this web page.

http://www.howstuffworks.com/question659.htm