Talk:Telephone numbers in the Americas

"540" is the area code for rural western Virginia, including the city of Blacksburg. It is not a premium area code.

The article does not say it is a premium area code. It says that in some areas 540 it is an exchange prefix for premium calls.

Mexico is not central america, I am editing.
 * You are right. According to one definition of North America, it includes all Central America; that's of course not the definition used here. According to the other definition, North America begins at the Isthmus of Tehuantepec, and therefore almost all of Mexico is in North America. On the other hand, Mexico is not part of the North American Numbering Plan, so the North America section must be divided accordingly.132.192.14.232 01:03, 23 March 2007 (UTC)

Calling to Mexican mobile phones
I think that calling Mexico mobile phones from outside Mexico requires a 1 after the country code but before the city code. (ie 011+52+1+81+8d for a Monterrey mobile) I believe this is a caller paid service. Unfortunately I can find little documentation of the caller paid comment, but the 1 after the country and before the city is on http://www.kropla.com/city_mexico.htm which I have been using for many years and consider a reliable and vetted authority. If I find a credible source for the caller paid portion I will add it here (or perhaps edit the page). Mdoneil 04:04, 19 July 2007 (UTC)
 * I found something on AT&T website, the link is in the article itself. It states that "1" is required before the area code when calling a mobile phone and "Calls to a mobile number in Mexico will include an additional per minute mobile termination charge (MTC)". I think the MTC is something like caller-pay. As AT&T is a major US telco, its website should be quite reliable. I will add something about this into the article.-- Joshua  Say "hi" to me!What have I done? 13:42, 19 July 2007 (UTC)

N0X/N1X exchange prefixes
As it stands, the article is stating that N0X/N1X exchange prefixes (i.e. codes with a middle digit of 0 or 1) were not permitted until 1995, which is not correct. Exchange codes of this format started to appear as early as 1973 in the Los Angeles area (213), and circa 1980 in New York City (212 area) due to demand. The 1995 date is correct with regard to AREA codes being allowed to have a middle digit other than 0 or 1 (the first such being 334 in Alabama).

Historically, the reason for N0X/N1X exchange codes not being allocated was because under the DDD plan numbers were all to be of 2L-5N (i.e. two letter, five figures) format, hence with no letters on the 0 or 1 dial position the middle digit could not be 0 or 1. That's why area codes were assigned specifically WITH 0 or 1 as their middle digit originally, in order to provide suitable discrimination. By the time Los Angeles was starting to run out of prefixes in the 213 NPA the all-number format was in use there, hence the ability to assign N0X/N1X codes, even though it meant a change of dial plan to accommodate them.

This whole section could do with a rewrite. PBC1966 (talk) 11:40, 31 July 2013 (UTC)