What do the iPhone 5 model numbers mean (A1428 / A1429)?
In deciding to go with blazing fast LTE capability in the iPhone 5, Apple was forced to release three different devices to meet compatibility with different LTE network standards worldwide.
The A1428 model iPhone 5 is the Canadian and US AT&T network GSM iPhone, including broad support for UMTS/HSPA+DC-HSDPA (frequencies 850, 900, 1900, 2100 MHz), GSM/EDGE (frequencies 850, 900, 1800, 1900 MHz), and LTE bands 4 and 17.