DCC Decoder Protocols

VRT327 · Posted: Sat Sep 06, 2008 2:31 am

A quick question on DCC Decoder Protocols.

I have recently purchased a Hornby Virgin Trains Pendolino set in which both power cars have a Hornby installed with a R8215 NMRA RP-9.1.1 / NEW652 medium plug decoder, when trying to give them a Loco number in preparation for a test run my NCE ProCab returns a “Can not read CV” from both units.

Hornby indicate that their protocol is XpressNet and NCE is a CabBus system.

Are the decoders on these systems interchangeable?

All the best,
Neil

TheBlacksmith · Posted: Sat Sep 06, 2008 8:09 am

The protocol refers to the ability of DCC systems to converse with one another or a computer system, it has nothing to do with talking to the decoders or models themselves.

However, the Hornby system is not guaranteed to be NMRA compliant, so it may have problems when you try to program it with an NCE system. Hornby have received quite a lot of criticism over thier non-compliance, whereas Bachmann went to the trouble of making their system NMRA compliant, and have recently received their certification.

Frankly, I would throw away the Hornby decoder and replace it with an NCE one.

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David Peters · Posted: Sat Sep 06, 2008 1:36 pm

The Blacksmith is right on the money here, I do not have DCC but read about it a lot and in the English Model railway magazines they have copped a walloping for not being N.M.R.A compliant, best idea would be as Blacksmith suggests get decoders that will work on your system! Cool

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VRT327 · Posted: Sat Sep 06, 2008 5:43 pm

Thank you very much Gentlemen for the advice on not only the decoders but also the Protocols.

As an aside Geoff, your Flat top 'T' is still going strong and is what I confirmed that the NCE was still operating properly.

Thanks again,

Neil

Aaron · Posted: Sun Sep 07, 2008 3:27 am

XpressNet and CabBus are protocols that allow your hand control units to talk to other devices (boosters, other hand controllers, etc).

XpressNet is the protocol used by Lenz, Roco and a few others maybe, including Ecos. Despite what Hornby say I'd NEVER connect a Hornby controller to my Lenz DCC system. Infact, I'd not connect a Hornby controller to a Hornby DCC system and, if I did I would not then connect it to the track.

CabBus is a similar but incompatible protocol that is used by NCE and MRC and again possibly some others. I don't like either of these systems, consequently what is compatible and what is not does not interest me.

Decoders from ALL manufacturers should (in theory) be compatible with ALL DCC systems. In fact this is not the case and Hornby decoders should be removed and replaced in all cases before any further trouble shooting takes place. I use this same diagnostic technique for anything featuring MRC decoders also and I am still thinking it can be useful around NCE too.

Good DCC systems carry full NMRA DCC warrants and good decoders feature the TCS or Lenz brand name.

Aaron
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VRT327 · Posted: Sun Sep 07, 2008 3:54 am

Unfortunately, I was silly enough to take the advice from the Hornby Tech team that indicated these locos would work.

As for the NCE equipment, you know how it goes, you buy what everyone else around you is using because at the time the quality is an unknown factor. At the time just about every DCC system I saw in Canberra was the NCE Power Pro, so that is what I have.

Hopefully this forum will put some good information into the general modeller population.

All the best, Neil

LaidlayM · Posted: Sun Sep 07, 2008 11:52 am

Neil,

I agree with Aaron about TCS and Lenz decoders, they are both excellent.

I think Aaron's comment "I use this same diagnostic technique for anything featuring MRC decoders also and I am still thinking it can be useful around NCE too." refers to decoders, not systems. Don't be ashamed of your NCE Power Pro, I don't think I have ever seen any criticism of them, I have one myself and it has been faultless.

Mark

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sunnysa · Beginner Joined: Jan 21, 2008 Last Visited: Jan 4, 2009

Basically agree with Aaron re Hornby decoders, and their systems too. Although the Elite now wears NMRA compliant stamp it is very clumsy accessing functions.
NCE systems are OK and probably the Powercab is one of the better value for money starter sets.
As to ease of use, I don't find NCE any easier than most other systems accept the ECOS which is the easiest system I have ever experienced.
Sunnysa

Aaron · Posted: Sun Sep 07, 2008 9:07 pm

miktrain · Posted: Sun Sep 07, 2008 10:13 pm

TheBlacksmith · Posted: Mon Sep 08, 2008 9:13 am

VRT327 · Posted: Sun Sep 14, 2008 7:34 am

Many thanks to everybody for your sage advice.

I contacted Hornby Tech team and asked if a replacement DCC chip could be obtained, they quickly responded asking a few questions then dispatched the new "NMRA compliant" decoders for my Pendolinos.
Both the powered and dummy motor units respond correctly to commands from the ProCab and work well as a pair.

With respect to Sony, they effectively killed off Betamax due to the price manufacturers had to pay for a license to produce the format, they obviously learnt with Blu Ray license pricing still being adopted ahead of HD format.

Thanks again, Neil