Lately, I've been having numbers show up on my cell phone's caller ID where the local exchange begins with 1. I thought 1, when it is used as the first digit in a phone number in the NANP denotes that the digits that follow are to be routed long distance. Has this changed?
A dialing plan is different from a numbering plan.
The world numbering plan assigns prefix 1 for NANP numbers, so a number that shows up with a leading 1 is just a full phone number.
The dialing plan in North America is (oversimplifying a bit) 1+10 means a ten digit NANP number, while 7D is an NANP number where the first three are the same as yours.
I've noticed the same thing, that CLID often has the leading 1, which makes sense since on calls from other countries, it starts with whatever the country code is, like 44 for calls from the UK. My telco also sometimes sends CLID that starts 1011-1NXX and is truncated, which I think is just a bug in the switch programming.
That's not quite how I read his post. From "the local exchange begins with 1", I thought he was saying that the calling number displays as NXX-1XX-XXXX instead of the expected NXX-NXX-XXXX. If so, I it could just as well be Caller ID spoofing by a junk caller.
Answer: No. In the North American Numbering Plan, both the area code (NPA) and the central office code are of the form NXX -- where "N" represents any digit except zero or one ("X" represents any decimal digit).
No legitimate North American phone number will have a 1 at the beginning, whether it is a ten digit number or a seven digit number.