I saw people wrote these technical specifications in iPhone 3G (http://en.wikipedia.org/wiki/IPhone_3G)
Quad-band GSM/GPRS/EDGE (850 900 1,800 1,900 MHz) Tri-band UMTS/HSDPA 3.6 (850 1,900 2,100 MHz)
So how to read the above technical specification correctly (ie to clarify these info so that the customers can understand)?