Decoders

[davidinyork]

Does anyone know why Hornby persist in designing their models for the outdated 8-pin decoders, when pretty much every other manufacturer of OO gauge models now uses the more capable 21-pin type?

[Robby_50]

I wouldn't call 8 pin outdated. Certainly it is older than the 21 pin socket, but if it does the job why change? It's perfectly OK for most steam locos and diesels where you want motor control and running lights. I do agree that for new models like Dapol's class 68 where a wide variety of lighting combinations have been included that a 21 pin decoder was essential. TTS decoders and Loksound are fine on 8 pin sockets ( although Hornby full sound loco's have 21 pin sockets ). 8 pin sockets also don't need a circuit board designing. The wires go direct to the socket. It must have been a lot easier for Hornby to DCC the old ex-Lima Diesels.

Its also far easier to alter wires on 8 pin or cut off plugs to hardwire decoders into older locos that don't have a socket. I have hard wired Bachmann class 158 and 170 DMU's Lima diesels and tender drive Hornby loco's and it would have been very difficult using 21 pin decoders.

We now have Next 18 decoders in some makes. The main advantage I can see is that they seem to have smaller sockets, so are easier to fit in smaller loco's, but are a bit of an overkill in steam loco's where you have only the motor to control.

Personally I find it great that we have such a wide choice of decoder formats

[Howbi]

I agree, Robby..........I only have 40 recently bought locos and none of them needs a 21 pin decoder but as several are Bachmann of course I have had to buy 21 pin decoders except in the case of the L & YR 2-4-2T where I decided to removed the 21 pin circuit board and fitted an 8 pin socket.......much more sensible........HB

[96RAF]

My guess regarding the 21 pin Hornby full fat sound would be that was the ESU sound chip at the time so they had to adopt that format.

Standardisation is an ongoing thing, look how edge connectors for various add-ons have changed inside PCs and laptops over the years, to say nothing about the different HDD types.

Rob

[davidinyork]

Thanks for the replies.

Should have mentioned that I was thinking mainly of diesels (I have no interest in steam locos). The example of Dapol's 68 is actually the one I was thinking of - the level of control possible in this (or even in the N-gauge version with a Next18 decoder) is much greater than with any of Hornby's recent models.

It does seem that they are getting increasingly behind the times here - Bachmann, Dapol and the various smaller suppliers have all gone with 21-pin for quite a while now.

[Fishmanoz]

Looking at the NMRA standards, the outdated connector is the 21-pin - not recommended for any new locos, only included on a legacy basis given so many are installed. The recommended is the Next 18. 

 

Then the only effective differences between 8 and 21 are the 3 Hall Effect inputs for brushless motors and the Train Bus clock and data lines in the 21 (I’m ignoring the speaker connections as they come as flying leads on 8-pin sound decoders anyway).

 

So David, what 21-pin features do you use that aren’t available on 8-pin?