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Digitrax Loconet

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  • Member since
    December 2004
  • From: Louisville
  • 584 posts
Digitrax Loconet
Posted by dbduck on Wednesday, March 27, 2019 2:47 PM

when running the loconet network does it have to be "daisy-changed" in linier fashion from device to device such as UP5s, UR91s & UR92s... or can splitters similar to ones pictured below be used to branch the network off in a different direction?

or this?

  • Member since
    June 2004
  • From: From Golden, CO living in Puyallup (Seattle), WA
  • 750 posts
Posted by Renegade1c on Wednesday, March 27, 2019 4:27 PM

Yes you can split it BUT you have to be careful that the cables are straight thru (or data cables). Most splitters reverse their pinouts. This means you would need to have the cables that come out of splitters be reversed so that the rail sync lines in the cables all match up correctly. This isn't so much important if you are only placing things such as UP5 but is very important if you connecting devices such as boosters or BDL168 or se8c signal decoders as they rely on railsync to be active. 

I would highly recommend buying a cable tester (not the crappy LT1 digitrax sells) but an actual cable tester. It will show your pin setup. Another way to think of it when making cables is that when looking at the clip side of the RJ12 connector the left wire should be blue and the rights should be white.

Remember commericial (off-the-shelf) splitters are reversed based on how they are built. Thats why a cable tester comes in handy. you can tell if its wired the way you need it or if you have to build a reverse cable the comes out of the splitter. 


Colorado Front Range Railroad: 
http://www.coloradofrontrangerr.com/

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  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Thursday, March 28, 2019 11:35 AM

 DO note that the actual Loconet portion of the wiring is just a pair in parallel so flipped or not, it does not matter. However, there are also 2 ground wires (flipping those also does not matter) and then the kicker - the two railsync wires - flipping those DOES matter - but only when using devices where the phase (fancy AC word for DC polarity) matters - BDL168 block detectors, especially if using Transponding, the new combo devices that are breakers, detectors, and trnasponders in one like the BXP88, and most importantly, any downstream boosters - the phase of the signal on the Railsync wires in the cable determins the phase of the signal appreasing on the Rail A and B outout terminals on the booster.

 So - depending on what is exactly present on the layout, using a splitter that reverses the wiring MIGHT actually be OK and cause no issues - until is does. Best practice is to be sure to use splitters and cables that do NOT flip anything, because what works fine today, in 2 years when you go to add a second booster and it doesn't work right you'll be wondering why. There are a couple of Loconet splitters being sold that are wired correctly so as to not flip the wires over. And if you don't want to make your own cables, Monoprice among others does sell pre-made 6 pin DATA cables (as well as phone - but the phone ones are the ones that are flipped, you want DATA cables for Loconet).

                                    --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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