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MRC Prodigy throttle control bus wiring?

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  • MRC Prodigy throttle control bus wiring?

    I bought one of the Extenders; plastic dual RJ-45 jack and 10 feet of flat cable. But I want a longer run to the next jack (I'll mostly be using my Prodigy Wireless), and I'll also need a few more connections right at the base station (control buses going both ways, a radio dongle and room to plug a throttle cable in too).

    I've got an RJ-45 crimper and connectors; has anyone got experience using Cat-5 cable for an MRC throttle control bus? If so, do you use the standard pinout, or something special (I can ring the cable out with a VOM if necessary, but it's a lot like work).

    I Googled up one reference to a module group that uses Cat 5, but they also say that after 5 modules you need a "control bus booster", which I guess I need to find out more about. I can get away with 5 or fewer sockets on my layout, but it would be nice if I could use a total control bus cable length of around 60 - 70 feet.

  • #2
    To answer my own question: After some more research on the net, I bought 100 ft. of Cat5E cable from a friend. To test, I crimped RJ-45s on each end, using standard 10/100/1000 Base-T Ethernet pinout. I made sure it worked as an Ethernet cable first. Then I used it to connect my Prodigy Advance hand-held throttle to the base station, also worked fine.

    Next step will be using some salvage cable boxes and jacks with punch-down connectors on the back to do a 3-way splitter. I want to use it for the radio dongle and bus legs going in two directions around my attic: 20 ft. to a dead-end jack, and 7 ft., then 16 ft. to two more jacks initially. I'll report how it goes.

    The color coding and use of specific pairs probably doesn't matter if MRC is using a slower bit rate than Ethernet, just make the cable "straight through". Or buy them already made-up.


    • #3
      De-cluttering led me to finish this project off. There were some Hubbell Premises Wiring boxes and jacks in a junk box at work; They had been salvaged from a dismantled 100 Mbit Ethernet installation a few years ago, and nobody minded me taking a couple:

      I also borrowed a punch-down tool (right) to make the connections. This box will be a 3-way splitter for the MRC control bus - one leg layout east, another west, and a 3rd for my Prodigy Wireless dongle. Because it's not Ethernet, I can get away with just jumpering each color code together:

      The final photo shows the box screwed to the layout frame near the MRC Prodigy base station.

      The Hub Div. Module Group is going to be switching to an RJ-45 based wiring scheme for our mostly-Lenz system. I don't know the details of the wiring yet, but it seems likely that I can just make a connector cable and use the same wiring for my MRC Prodigy as I'll use for Lenz control bus at shows. I'll post more when I know the details.


      • #4
        I've now run all the Prodigy throttle control bus I expect to need: I had three jacks on the west side of the attic, and I've added three on the east. Total bus length is about sixty feet. I only have one plug-in throttle, but it doesn't seem to have any problem with the distance or how the Prodigy control unit sits in the middle.

        I'm still using salvaged Hubbell boxes - this shows how they go together. The jacks snap into the face plate, and have color coding to match the wires. I didn't mention it earlier, but the punch-down tool is for what Ma Bell called a "110 block", rather than the more common "66 block". Note also that many punch-down tools have one bit that cuts the wire and another that doesn't. I needed both for this daisy-chain.

        This is an RJ-45 crimper, with the wiring diagram I worked from and a termination that came out right first time (doesn't always happen) [:-censored]

        I made a mount for one of the boxes from a 2x4 - it's screwed to the underside of the layout, but I backed that up with glue, so it's clamped while that dries. It seems solid, but the proof will be if it is sturdy enough for visiting operators.


        • #5

          L&N nut



          • #6
            First, I can say that the box above has stood up to both helpers running trains at open houses and ten formal operating sessions.

            But I'm bumping this old thread because I've resolved some problems with my initial installation:

            When I built my 3-way splitter above, I ran one wire from the Prodigy Advance base station to it. From it, I ran control buss clockwise 20 feet to a single socket, counter-clockwise 50 feet with 9 sockets scattered along the length, and directly connected the Wireless transceiver to the 3rd port. This worked, but the only socket I could plug the wireless dongle into was the splitter's. Anyplace else would work under light load but fail at an op session.

            Last fall I thought about the signal characteristics and decided I'd made a mistake. I tried connecting each of the three feeds directly to a port on the base station and made the splitter into a throttle connection box on one of the feeds. It seemed to work better, so I did some experimenting with wireless dongle location which I'll cover in a future post. I ran the new arrangement past MRC's support person at W. Springfield last month; he said I was on the right track.

            He also told me MRC offers a 'powered extension plate' (#1502, the picture should include a wall-wart) which they recommend for 5 or more cabs. The original Prodigy Advance manual had hinted about control bus regeneration of some sort, but I'd never found a product which actually did that. I plan to get one as part of a project to extend my control buss. I'd be satisfied with 12 more feet and two sockets, if I could get 25 more and 3-4 sockets that will be great. I'll report as it progresses.


            • #7
              Documenting a bit more work on my MRC Prodigy Advance throttle bus:

              The 'keystone' RJ-45 jacks I've been using show where to punch down each pair by color-coding. But this set of jacks offer two location options for Orange and Green with no explanation which is which. Luck led me to choose the compatible way first try.

              The other lesson I learned today is that premium Cat5 cable uses stranded wire. That certainly extends the life of cables that are handled a lot. But while they work with standard 110 punch-down terminals, there isn't much margin. I tried 'double-punching' one cable atop another, but contact wasn't reliable. Took me a while to solder a splice, which doesn't seem to bother the MRC buss much.


              • #8
                In February 2018 I bought an MRC 1530 WiFi interface for my Prodigy Advance:

                + $85 from an on-line store

                + Signal has no problem finding its way around my 3' x 9' brick chimney, unlike the Prodigy Wireless handsets & dongle.

                - Documentation printed on a business card is inadequate: got me up and running

                + Handled two phones running trains OK

                - A bug in the browser interface prevents you from deleting Roster entries

                But just after the 1-year anniversary, something went wrong. WiFi throttles couldn't acquire locomotives. Once I found the EngineDriver log, I saw "Cab Number 2 > Last Operational Cab Number 0". The last cab (Prodigy Advance etc. polls cabs one after another, so telling it to skip unused numbers helps performance) had been 8, 7 didn't change the message. I tried software Reset. I had an email conversation with MRC Support. I took it to a nearby Hub member's house, where it gave the same error on his MRC base.

                MRC said they'd repair or replace it for $85, but didn't have stock on hand for immediate replacement. I replied "thanks for the fast response, but the price is not attractive" and ordered another. I'll probably dissect this one to 1) see if I can read the firmware out and 2) looks for a thermal failure. The enclosure has some vents but when idle gets up to body temperature after a while. If it generates more heat under load, I'll consider removing the enclosure for better cooling.


                • #9
                  Tried out the new MRC 1530 WiFi unit today, it works. However when I started setting my Roster up, I got bitten by the "can't delete Roster entries" bug: I didn't figure out Default Functions before starting, so now I have a Roster from which EngineDriver only shows Light, Bell and Horn buttons, with no access to F3 or above. EngineDriver lets you set function labels too, but I haven't figured out how to override the MRC's on my own tablet; but assuming I can, that will be of little help to visitors.

                  Years ago, LVRalph and others discussed a "layout operators' consensus" assignment of function buttons for Brake etc Clearly, it's time to dig that up and create the infrastructure...