Moving 7D -> 8DThe Problem - Moving Directly from 7D to 8D
Most plans call for a move to longer than 8D dialed numbers first. I believe this would be a bad step. Unless a move to 8D is guaranteed by contract or law, I do not expect any 'temporary' longer numbers to be shortened to 8D. The complete loss of shorter than full length dialing, even with an enforceable guarantee of allowing 8D "in the future" is a burden that I believe should be avoided. The world won't end, but for many people using the telephone will be less pleasant. Therefore I have a hard time supporting any 'temporary' moves to 10D, 11D, or 12D dialing.
Numbering Plans and Dialing Plans
7D Dialing Plan Gap
As 1+ dialing is more common that 0+ dialing, the choice would be 0. This is a tough decision to make as dialing 0+ for Operator Assistance is an old part of the current dialing plan. But I believe that it can be done IF we give subscribers something in exchange. A direct move to 8D numbers are that exchange. The a staged transition will be needed, as one cannot permissively have 0+10D and 0+7D numbers. So the actual transition from 7D to 8D will have to take place AFTER 0+10D is replaced.
Clearing the Zero
It would be best to do this change in conjunction with expanding the NANP to a
full 12D number from the current full 10D number. Not only could the publicity
be shared, but the full 12D pattern of NPAX-dnxx-xxxx (with the new NPA being four
digits, and 'd' initially being zero) would be reinforced.
Keeping Operator Assisted|
While not used as widely as it once was, I do not wish to destroy operator assisted dialing. "0" and "00" will continue reach local and long distance operators, I suggest that the "0"+10D dialing be replaced by "001"+10D (which will eventually be "001"+12D). This will require adding a timeout to "00" dialing. While it would be possible to move to a "00"+10D/12D system, foreign visitors may find that confusing. For most of them, 00+1 is a call to the NANP and 00+n is an international call to some other area in the world. That confusion is unnecessary.
In addition, with the timeout added to "00", it would be possible to allow "00"+ as "Sent Paid International" along side the current "011"+ access. This would help foreign travelers in their dialing and make the NANP dialing system more unified with the rest of the world. "01"+ would remain as "Operator Assisted International".
Overlay Area Considerations
I compare this to the current 10D overlay system. 10D numbering is required when the first new exchange in an overlay is assigned, but it may be years until that overlay is 'visible' to the general public. In these 10D overlays, the first three digits of the number are redundant initially, and even after the overlay becomes well known those three digits serve a purpose that could be served by one digit.
The cost of having a uniform numbering system within each country requires that the entire country uses the same length local number. The 'cost' of dialing the 'redundant' zero is smaller than moving to 10D, 1+10D, 12D or 1+12D dialing. I believe the benefit is worth that cost.