# What are Decoders for?



## Evan (Sep 1, 2010)

I don't know what there for?


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## tjcruiser (Jan 10, 2010)

Evan,

I've never seen or used one myself, but a Decoder is one of the required brains for a DCC (digital command control) train system, for which one transformer can independently control several trains on one track. The smart systems send out power via a very-rapid set of step-like voltage pulses, sort of like a black-and-white bar code on something you would buy at a store. Each loco needs an onboard Decoder chip that monitors the pulses, looks for a unique signature to see if the "signals and directions" are meant for it, and, if so, operates accordingly (speeds up, stop, etc.)

I had learned a bit about this in another thread, and will quote myself here. Take a look at the link at the end of this ... I found it very useful to understand how DCC works.

Cheers,

TJ



tjcruiser said:


> Gents,
> 
> I did a little reading, and it all comes down to something called "zero stretching" which is essentially breaking the conventional constant-voltage DC power into a stepwise series of square-wave power pulses.
> 
> ...


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## Evan (Sep 1, 2010)

tjcruiser said:


> Evan,
> 
> I've never seen or used one myself, but a Decoder is one of the required brains for a DCC (digital command control) train system, for which one transformer can independently control several trains on one track. The smart systems send out power via a very-rapid set of step-like voltage pulses, sort of like a black-and-white bar code on something you would buy at a store. Each loco needs an onboard Decoder chip that monitors the pulses, looks for a unique signature to see if the "signals and directions" are meant for it, and, if so, operates accordingly (speeds up, stop, etc.)
> 
> ...


So since I am getting a DCC system will I need a decoder to run more than 1 engine?!


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## tjcruiser (Jan 10, 2010)

I hope I'm not wrong in saying this (again, I am NOT a DCC guy), but I believe that you'll need a decoder chip inside EACH loco that you plan to run.

TJ


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## Evan (Sep 1, 2010)

tjcruiser said:


> I hope I'm not wrong in saying this (again, I am NOT a DCC guy), but I believe that you'll need a decoder chip inside EACH loco that you plan to run.
> 
> TJ


Okay Thanks. I have a few more question. How much do each chip cost? And in your oponion what is better, DC or DCC?


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## tworail (Apr 13, 2006)

DC would imply traditional analog control of trains, where you would need separate electrical blocks to control multiple trains. One DC controller per train in most cases.

DCC allows an almost unlimited amount of locomotives to operate on the same electrical block. Each decoder has a digital 'address' that receives commands from the digital control unit. The decoder decodes the signal and sends the appropriate commands to the motor/lights/sound/etc. So in theory you could operate a couple hundred locomotives simultaneously on one layout.

Or something like that


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## T-Man (May 16, 2008)

Evan, none of us have stepped up on the soapbox to declare themselves experts. All the manufacturers have excellent sites on information on their systems. All you really need to do is read up. The decoder goes in each engine to understand the DCC computer.Here, we would be more interested in what you get and how easy it is to use. You can also ask what other members are using. Stationmaster is probably the top dog for that but he his lost up there somewhere on the Great Lakes. Try checking out the Bachmann site?


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## tworail (Apr 13, 2006)

http://en.wikipedia.org/wiki/Digital_Command_Control


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## tankist (Jun 11, 2009)

T-Man said:


> All the manufacturers have excellent sites on information on their systems. All you really need to do is read up.


looking for information is just way to much work. why bother googling and looking for it yourself if you can make 0 effort and just post uninformed questions on a forum?


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## Evan (Sep 1, 2010)

Thanks all! I did some searching on Youtube too. Some people didn't even use decorders to control more than 1 engine. I will be probally getting the Digitrax Zephyr controller and just play around with it. I heard that controller is good, is it true?


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## Bman (Aug 24, 2010)

I have the Digitrax Zephyr controller and I think it works great. It's easy to set up and once you get the hang of programming it's not that bad to operate either. The harder part can be installing the mobile decoders in the locos. The Zephyr only allows you to operate 1 DC loco at a time, besides having the decoders in the locos is what DCC is all about. With the decoders you can control lighting, speed match different locos and start, stop and control the speed of each one independently.
I enjoy DCC much much more than the old DC (analog) system
bman


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## Evan (Sep 1, 2010)

Bman said:


> I have the Digitrax Zephyr controller and I think it works great. It's easy to set up and once you get the hang of programming it's not that bad to operate either. The harder part can be installing the mobile decoders in the locos. The Zephyr only allows you to operate 1 DC loco at a time, besides having the decoders in the locos is what DCC is all about. With the decoders you can control lighting, speed match different locos and start, stop and control the speed of each one independently.
> I enjoy DCC much much more than the old DC (analog) system
> bman


WOW! Thanks alot Bman! This helped me the most!


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## tankist (Jun 11, 2009)

i guess after all you decided to not read the very long wiki article tworail posted .
:laugh:


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## Evan (Sep 1, 2010)

tankist said:


> i guess after all you decided to not read the very long wiki article tworail posted .
> :laugh:


Lol. No I did read it but, since I'm new a modeling I didn't really get it.


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## tankist (Jun 11, 2009)

modeling experience has nothing to do with it. i find that the intro paragraph summarises the consept quite well.
i think i already posted the link to http://www.dccwiki.com/Main_Page
this resource has both beginners and advanced information. 

PS: for the sake of your engines lives forget about running engines no equipped with decoder on DCC layout. this functionality is only good on paper. in reality engines will heat up (what happens when you put AC power to DC motor?)
you will need a decoder for each engine.


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## Evan (Sep 1, 2010)

tankist said:


> modeling experience has nothing to do with it. i find that the intro paragraph summarises the consept quite well.
> i think i already posted the link to http://www.dccwiki.com/Main_Page
> this resource has both beginners and advanced information.
> 
> ...


Thanks tankist. But I'm done with this. I learned lots of stuff and I decided I will get the Digitrax Zephyr and play around with it. I learned lots of stuff with decoders. Engines already equipped with DCC don't need decoders. At least that what I think. Please tell me if im Wrong.


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## tjcruiser (Jan 10, 2010)

Evan said:


> Engines already equipped with DCC don't need decoders.


Engines already equipped with DCC already HAVE decoders in them.


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## Evan (Sep 1, 2010)

tjcruiser said:


> Engines already equipped with DCC already HAVE decoders in them.


Lol, that's what I meant. You don't need them because there already in there.


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## Lester Perry (Nov 7, 2008)

I have had DCC for about 5 years now. The reason I got it is sound, If you have the money the sound can be amazing. In my opinion if you have a small layout wit just a couple of locomotives you might be ahead of the game staying DC. If you are just starting in the hobby and have not purchased very much or maybe nothing. Then start with DCC it is here to stay and I think DC operation is on the way out. 20 years from now it will be gone except for the serious collectors. I have the MRC Prodigy and like it. I feel it is much simpler to use than Digitrax. I will malso suggest that you go wireless. I used several other systems before buying mine I feel that helped in my decision.


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## tankist (Jun 11, 2009)

Evan said:


> Lol, that's what I meant. You don't need them because there already in there.


saying "_Engines already equipped with DCC don't need decoders._" 
just like saying "cars don't need wheels because they already have them" 

_:shakes_head:_


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