6 Pin DCC Plug
The NEM 651 or 6 Pin DCC Plug is one of the standard plugs used for Locomotive Interfaces. The plug is integrated into the decoder (or possibly on the end of a loose wiring harness) and mates with a fixed 6 hole socket mounted on the locomotive chassis. The 6 pin version is known as the small size and is intended for use in N gauge locomotives.
DCC-ready locomotives with 6-pin sockets are shipped with a factory-installed 6 pin blanking plug that shorts the rail pickups to the motor terminals in the absence of a decoder. This plug must be removed to install the decoder. The blanking plug must be replaced if removing the decoder and returning the locomotive to analog operation.
This table depicts the pin assignment of the NMRA 6-pin plug or 6-pin socket. Although the wiring is designed to work properly one way round, no harm is done if it is inserted the other way round by mistake (but it won't work correctly). This plug and socket combination is identical to the NEM 6-pin plug and socket (defined by NEM 651) used in Europe.
Pin 1 should be clearly marked on the plug and socket with a small triangle or dot.
|pin 1||Orange||Motor Right|
|pin 2||Grey||Motor Left|
|pin 3||Red||Right Rail|
|pin 4||black||Left Rail|
|pin 5||White||Front Headlight (F0)|
|pin 6||Yellow||Rear Headlight (F0)|
Note that there is no common positive supply wire for the headlights, the headlights are supplied by rectifying the supply from the rails as shown below. This circuitry will already be present in a DCC-ready locomotive equipped with a 6-pin socket and headlights.
The 6-pin connector has the following specifications:
- 1x6 six pins at 0.05" pitch
- 0.5A contact rating (maximum sustained load)
- 0.75A peak contact rating
The contact ratings are for the individual pins of the connector only and do not reflect the capabilities of a particular decoder or requirements of a particular locomotive. For example, if a locomotive's maximum sustained motor current is over 0.5A, this plug and socket should not be used.
This information is based on NMRA RP-9.1.1 Electrical Interface & Wire Color Code, which also describes the medium and large sized alternative plugs.
NEM Standard: in French.