Postby ConducTTor » Sat Aug 18, 2012 3:48 pm

dileTTante wrote:
ConducTTor wrote:Bill, you don't need a command station with the JMRI. It IS the command station - especially when controlled from a pc which gives you much more functionality than the iPhone apps (I use WiThrottle). The only thing really needed for the JMRI is a power booster if you're planning on running anything more than 2 locos.
I think this is not correct. JMRI and computer will not drive a layout with just a DCC booster. You need the extra hardware to feed the digital signals to the booster.

I just re-read this. Let me clarify:

My assumption was that the JMRI would be used with the SPROG. Hence, the SPROG needs a booster. Or am I wrong again?
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Postby railtwister » Sat Aug 18, 2012 7:02 pm

ConducTTor wrote:I just re-read this. Let me clarify:

My assumption was that the JMRI would be used with the SPROG. Hence, the SPROG needs a booster. Or am I wrong again?

Actually, the SPROG II and the SPROG III are both USB connected computer interfaces with built-in boosters. The Sprog II has a relatively low power booster/power supply (12v@1.5a), while the SPROG III has more power (I believe 2.5amps@ up to 20v), so the SPROG III is designed to run a layout, while the SPROG II is really only meant to test-run (using the programming track) whatever programming you have done with it. There is also a new product called the SPROG/Boost to use with the SPROG II to increase it's power (up to 2.5 amps). For more accurate details, go to the website of the USA importer at:

TAM Valley also has a low cost booster for about $42 (less power supply) that may also be a possibility:

I'm pretty sure the Digitrax PR3 can't be used as a booster, nor can it test run something you've programmed with it, it needs to be hooked up to a Digitrax system to do that. However, with a computer and without a DCC system, it can be used as a stand alone programmer and supposedly can manipulate sound files on Digitrax brand sound decoders (if you are lucky enough to get it's software to work!). I was able to get mine to work using JMRI DecoderPro on my Mac desktop, both of which are not supported by Digitrax. Unfortunately, I was looking for something portable to take to shows for programming with my two modular groups, and my Mac desktop isn't portable enough. Plus, without it's own software, the PR3 won't do sound files, so I went with the SPROG II after buying a PR3 and a Netbook for programming. After my experience with the PR3, I will have nothing to do with Digitrax Sound Decoders, although I still think their Zephyr Xtra is the best bang for your buck in a DCC starter system.

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Postby WillYart » Sun Aug 19, 2012 10:11 am

I've read the thread and feedback with much interest while simultaneously reading Don Fiehmann's book. My understanding is that something has to generate the DCC waveforms; they are like TCP/IP but extremely simplified for use on the model railroad. Normally hardware ("command station" or custom home built circuitry) does that.

Interestingly somebody has taken the trouble of emulating the process in software, with output to a serial interface which can be used as a substitute for a command station. The software is:

For Windows ("DDW"): http://home.snafu.de/mgrafe/index_en.htm

For Linux ("DDL"): http://www.vogt-it.com/OpenSource/DDL/

Their site says "The program generates all the information necessary for operation of digital locomotives and solenoids via the serial interface. Only a simple booster connected to the serial interface is necessary." According to http://home.snafu.de/mgrafe/news_en.htm, as of July 2011 DDW works with JRMI.

Don't want to tinker with DDW though. I like the human interface software that comes with the Roco / Fleischmann Z21 but I better not spend my limited funds on it right now. So... I'm considering using the SPROG 2 with JMRI and a smartphone throttle. See http://www.youtube.com/watch?v=pq_R75WJ ... re=related for a test run of exactly this setup.

I don't think I need SPROG 3 because I'm only running at most 2 trains simultaneously. More amperage = heavier gauge wire needed to avoid melting the coating off the wires. Also more power = more of a chance of melting locomotives or welding them solidly to the track if there is a short and circuit protection fails.

Too bad SPROG doesn't seem to support railcom (correct me if I'm wrong!). But that's nonessential.
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