I just purchased an Athearn Roundhouse GE AC4400CW. It has a 21 pin plug/DCC ready. Im looking at installing this decoder (ESU loksound v5 21 pin). Does this mean i can just unplug the jumper plug on the motor light board and plug in the decoder?
Yup. You need to connect a speaker too, if that isn’t already installed in the loco. Some, like Rapido, sell the DC/DCC Ready version with the speaker already installed so all you really need to do is plug in the decoder.
–Randy