2 Main types of chip exist in N Gauge, Next18 as the new kid on the block in the UK, and NEM651 or as it is more commonly know, the 6 pin decoder.
Next18 takes N Gauge DCC to the next level of complexity. A standard Next 18 chip supports motor control, independent control of front and rear headlights. As well as this it also provides a very impressive total of 6 auxiliary output functions.
The entire connector is only 8mm long and 5mm wide. Because of their small size, connector pins are only rated for 500 milliamps, so some connections are allocated two pins. The result being that although there are 18 pins, some are redundant, and the 18 pins provide only 12 discrete connections.
A key feature of the interface is “smokeless symmetry”. Pins are assigned in a somewhat symmetric fashion, such that if installed backward, no harm is done to either the locomotive or the decoder; it will not function properly, but nothing will be damaged or melted as was oft the case with previous standards of DCC Chip.
NEM651 / 6 Pin DCC
Before Next 18 N Gauge modellers converting to DCC would ordinarily use an NEM 651 6 Pin Chip.
Much simpler in looks and ability. The 6 Pin Decoder controlled typically just motor and directional lighting. Often referred to as a 2 function decoder, quality and reliability varied significantly between manufacturers.
The NEM651 standard also catered to the older locomotive, something you cannot do with Next18. For this you could also get the decoder with 6 wires instead of pins, or a wiring harness to convert. This was great for older locomotives from before DCC became mainstream. With a bit of work you could convert almost anything to DCC control.
Sitting here and writing this in 2020 Next18 is now becoming very common. Most if not all manufacturers are upgrading the chassis on their latest releases to Next18 control.
However it will be a long while before 6 Pin becomes a thing of the past due to the sheer number of locomotives and multiple units released over the last 10 years. One big benefit of the 6 pin standard is cost, it’s been around a long while and as such entry level decoders can be bought online brand new for less than £10 each. I’m sure Next18 will get that way soon, prices are already starting to fall as the technology becomes more common.
I’ll never get a chip in there!
Oh yes you will. Probably won’t be cheap but within reason there is a chip to fit even the tiniest of space. Most of the mainstream manufacturers offer ‘mini’ versions of chips for a premium.
Alternatively a right angled chip may be just what you need to fit in the strangest of places. The are a popular option for a number of tender drive steam locomotives, and some small diesel shunters
The most common manufacturer for these is Bachmann, other options do exist.
Personally, I’ve also taken another option, perhaps not ‘textbook’ but effective none the less.
The above is a 6 pin extension harness available from DCC Concepts and other providers. Enabling you to site the decoder where this is more space, perfect for those of us with sausage fingers, or a taste in small pieces of rolling stock.