What is NPA NXX ?

I am in the middle of ordering some data circuits for our new office and the vendor asks me for the address of the building where the circuits are going to be terminated. I give it to them and they come back with “what is the NPA NXX??” of the location. Now, I should admit that I haven’t been provisioning hardcode data circuits, but have ordered a bunch of T1s and DS3s during my career. I thought this was come kind of technical spec and swallowing my pride, asked the vendor what NPA NXX means.. and the answer..

there are no dumb questions 🙂
the first six digits of a phone number

Looking up on the web, gave me this information

NPA = (Numbering Plan Area code) The area code of a telephone number in the NPA system. The first NPA codes used 0 or 1 as the center digit, such as 201, 212, 301, 312, etc., designated as “N0/1X.” After July 1, 1995, all digits 0 through 9 are valid as the center digit, designated as “NXX.”

All I can say is “live and learn” :).