Different codes for Costco and Sams Club, etc.
http://www.retrevo.com/samples/HDTV-Decoder-Costco-Reseller.html

Decoder for major brands
http://www.retrevo.com/samples/HDTV-Decoder.html

a=2008
b=2009
c=2010
d=2011
e=2012

LN=LCD (CCFL) North America
UN=LED North America
PN=Plasma North America

The smaller the number the less features it has. so the 450 will be an entry level or value tv and the 730 will be the model with the most features.

<div>I'm trying to find out what the letters after the model numbers mean. Any help is appreciated. Example: Samsung UN60EH6000<b>FXZA

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