The only difference between the two decoders is the shape and size. The CN is shaped to fit between the parts of the frame that stick up on both ends of the Chinese made Atlas RS and RSD series of locomotives and is slightly longer than the CN-GP. Refer to the photo above to see a comparison of both types.
As the name suggest, the CN-GP is designed for the Chinese made Atlas GP series. Both of these decoders can be used in other locomotives as well, sometimes requiring a little more modification to the frame. The table below lists all of the locomotive types that I've installed these type of decoders in so far along with brief notes about the installation. If I have related material in this blog, there will be a link to it. This table will be updated whenever I discover another locomotive that the CN or CN-GP decoders can be used in.
|Make and Model||Decoder type||Notes|
|Atlas GP7 and GP9||CN-GP||1995-1997 releases - see instructions|
|Atlas SD7 and SD9||CN-GP||Old release made by Kato - see instructions|
|Atlas Classic RS1||CN only||Reverse board locations - see instructions|
|Atlas Classic RS3||CN only||See detailed instructions|
|Atlas Classic RSD4/5||CN only||See detailed instructions|
|Kato SD40 or SD45||CN or CN-GP||Requires slot on top of frame for wires|
|Kato U30C or C30-7||CN or CN-GP||Requires slot on top of frame for wires|
|Life Like C424||CN-GP||Requires slot on top of frame for wires and reverse board locations, see instructions|
|Life Like GP60||CN-GP||Minor frame modification, see instructions|