CC = Cocoa electronic (I believe traded on enext-comdty)
CO = ICE Cocoa composite
ECO= ICE Cocoa electronic
RCO = ICE Cocoa pit traded
C = CBOT Corn pit traded
NC = Corn composite
ZC = Corn composite
This is way outdated, and missing many of the codes, but it is a good start
http://www.tfc-charts.w2d.com/specs/
This one is more detailed, but not 100% either
http://www.barchart.com/futures/specifications.php