This is the A1428 model of the iPhone 5, introduced by Tim Cook at an Apple Special Event on 12 September 2012 (2012-09-12). This variant is sold only in the United States, Canada, Puerto Rico and Mexico because of the LTE bands it supports; the N42AP is sold in other countries, as well as the United States and Canada.
There are actually two versions of this model; when T-Mobile USA began to carry the iPhone 5, Apple made a tweak to this model to support HSPA+ on AWS bands.[1] A carrier update enabled LTE over AWS for all of these iPhones, but using HSPA+ over AWS requires a new unit. Apple provides instructions [Archived 2013-04-14 at the Wayback Machine] to check if an iPhone 5 can use HSPA+ on AWS. The name used in firmware is iPhone5,1.
