Simply connect the tester to your command station or the LokProgrammer. It enables you to test any decoder without exposing it to any external factors caused by the locomotive that may influence its performance.
It has all commonly used interface sockets for connecting a decoder for the smaller scale models:
Besides a 6-pole NEM 651 socket and the 8-pole NEM 652 socket, it also has an 21MTC interface as per NEM 660, a PluX22 socket as well as a Next18 interface. Decoders without any interface can be contacted with individual terminals.
Now there is an extension board that enables you to also connect our large scale decoders to the Decoder Tester.