What is Tri-band 2G CDMA (800 (CDMA over ESMR), 850, 1900 MHz) in Iphone 5 CDMA model? In this page http://en.wikipedia.org/wiki/Iphone_5, it said

iPhone 5 CDMA model (A1429) support "Tri-band 2G CDMA (800 (CDMA over ESMR), 850, 1900 MHz)."

So what does it means?

So before iPhone5, CDMA customers can't make the 2G call or something like that?

Why Apple support very old 2G technology in iPhone 5? 

Is it cos CDMA customers complained they can't make 2G call on iPhone 4, 4s &amp; that is why Apple start to support 2G CDMA on the iPhone 5?
It means its compatible with 3 bandwidth for 2G : 


800 MHz (CDMA over ESMR)
850 MHz (GSM)
1900 MHz (GSM)


800/1900 is mostly used in the USA and Canada. It's quite usefull to use 2G since 3G has not a coverage as wide as 2G.