The DHWHP harness is part of the Digitrax Easy Connect system--a DCC medium plug on one end for connection to the locomotive’s DCC socket and a Digitrax 9-pin plug on the other end for connecting to the decoder’s 9-pin socket.
The Digitrax 9-pin connector is used by many other DCC companies, too! It’s easy to unplug the decoder from the locomotive.
This is useful if you have many locos to equip and a limited budget. It also makes it easy to unplug a decoder and try a different one if you suspect a problem with a decoder. 1. Simply remove the “Dummy Plug” from the DCC socket on the factory circuit board in the locomotive and plug in the DCC medium plug end of the harness.
2. Plug the 9-pin plug into the 9-pin socket of the decoder. The plug is notched to fit easily into the socket in only one orientation.
3. To run your DCC ready locos on DC with the decoder removed, just remove the decoder and DHWHP harness and reinstall the dummy plug that came with the loco.
4. The DCC medium plug supports F0F (White) and F0R (Yellow). The harness has two additional function leads (F1/Green and F2/Violet) for decoders that have the additional function capabilities.