21 pin decoder in a loco which has no functions, lights or flickering firebox?

[Splatz]

Recently bought R3997 Princess Coronation City of London from the Hornby site, and whist it is a great looking loco, I noticed it had a 21 pin decoder socket, and I was wondering what was the point of fitting a 21 pin decoder?

Surely this is a pointless decoder choice which comes with way more functions and none of them are usable in this loco.

[96RAF]

But it could have as well as smoke, etc

[ellocoloco]

A 21pin decoder usually takes up less space than an 8pin decoder with harness and is probably the same cost so although the loco does not have extra features, it is a sensible choice.

[Splatz]

But it could have as well as smoke, etc

 

 

Are you suggesting Hornby only put a 21pin socket in this loco to future proof anything I might want to add to the loco?

 

 

 

 

[P-Henny]

So far, all the evidence points to the water vapour smoke generator ONLY being a factory fit option and not likely to be made available as an 'after market' upgrade. However that said, it makes economic sense to standardise on a PCB design to fit numerous different loco types including those with factory steam. The standardised PCB having a 21 pin socket to maximise flexibility.

As ellocoloco says, the 21pin requires less loco real estate compared to a harnessed decoder like the 8 pin.

[ColinB]

Having tried to fit an old TTS decoder into a new P2, Hornby are probably fitting 21 pin sockets as their 8 pin HW7000 will probably not fit. As someone said it is probably a standard fit. One one loco they did put 21 pin DCC ready on the box but fitted 8 pin sockets.

[Kim-344602]

One big advantage of the 21 pin decoder is that it gets rid of the need for the speaker wires to be soldered the the decoder. That allows a much better choice of speakers as if retrofited, they will plug into the mount. Also, some manufactures like Heljan are factory fitting speakers in some models so all you need to do is replace the blanking plug with a decoder.

The 8 pin socket was a simple upgrade from the early days when you had to solder the flying leads from the early decoders. At the time, most were motor control and perhaps lights only and the "plug and play" of the 8 pin is limited. Even the 21 Pin is being superseded by the PlusX and Next18 sockets.

Easy to get adapters to allow you to plug an older 8 pin decoder into a 21 pin socket but not the other way round.

[81F]

Bachmann has been fitting 21 pin decoders to its steam locos for sometime and they didn't have lights etc. The ones that spring to mind are the Robinson 2-8-0s and I think their Cities as well.

[Peter Stiles]

I seem to recall that the 8-pin DCC socket/adaptor had moved to "deprecated" status in the standards and Hornby getting stick for continuing with the 8 pin layout..

[Fazy]

When I bought the bachmann class 20, 24,25 and 47 all had 21pin decoders 20ish years ago the class 20 didn’t have lights but the pcb had pads to add lights which I did later. Hornby is a bit slow on such things. Only moving to the 21 pin decoders when everyone else are moving to the Plus x and Next 18.