There are no real restrictions on LocoNet wiring with respect to wire pairs. Most Digitrax customers choose to use 6 wire Telco type flat ribbon cables because they are cost effective, simple to wire and give superior network performance. We engineered LocoNet to use 6 wires because of several advantages outlined below.
LocoNet can actually run on just 2 or 3 wires. LocoNet can support a total cable length of up to 1,200 feet. No two devices should be connected by more than 600 feet of cable. This allows for the network to be split & branched in a free form style with no stringent connection rules for network transmission. You can "tree" or branch out network stubs wherever it is convenient for the layout and debugging or servicing. The single network termination needed is provided by the Command Station. We do not recommend looping the network back on itself.
You can purchase ready made 6 pin male RJ12 to RJ12 jumper cables of various lengths from many sources. Be sure to use 6 conductor and not 4 conductor plugs and wires. Alternately, you can crimp your own jumper cables. LocoNet cables should be wired pin 1 to pin 1. When you hold the plug with the tab up and look into the end of the connector, you will see, from left to right, white-black-red-green-yellow-blue wires. This arrangement is called a “reversing” cable in the telecom industry. The UP5 is "reversing" in that all pin 1s of the RJ12 jacks connect to one another.
1) In a 6 wire flat configuration, as crimped onto a RJ12 6 pin style plug, the left 3 wires are effectively a "mirror" image of the right 3 wires. This allows you to "daisy-chain" outlets without worrying about whether the cables are "reversing" or "non-reversing."
2) There are 2 ground and 2 LocoNet data connections, so the effective "loop resistance" is lower due to paralleled wires. This makes it possible to run LocoNet over greater distances than other command control systems.
3) If a ground or signal connection is broken or intermittent the network can still maintain a reliable connection. These types of faults are the greatest nightmare to locate and fix!
4) The two outside wires, typically Blue and White in a 6 conductor Telco ribbon, actually carry opposite phase copies of the master system rail packets, this is called RAIL SYNC. Because these are broadcast differentially in a single cable, we can accurately and reliably tap a remote Track booster anywhere along a LocoNet cable run. We can do this many thousands of feet from the Master Packet generator (Command station) with very good signal fidelity, even in the presence of a lot of noise and interference! Also, this signal is capable of supporting a number of low current draw modules that can tap on anywhere in the network.
5) The balanced nature of the cable and the way the signal currents propagate in this "RF Quad" configuration allow the lowest possible RFI radiation outwards, and EMC susceptibility or inward interference pickup. This is a good thing. This is part of the reason Digitrax's LocoNet handily passed the FCC Class B radiation Certification requirements.
6) The LocoNet philosophy and architecture were carefully crafted to allow "free-form" wiring with no termination or "linear-bus" restrictions. You can "star", "tee" into, branch or expand the network any way that is convenient for you. If you do choose to "loop" the wiring back on itself (like a snake biting its tail) be sure that the outside 2 Railsync wires have a matched polarity! The center 4 pins of the RJ12 can be plugged in either orientation.
These are the reasons we would recommend the loop around the layout be a 6 conductor ribbon type wire. The wire guage in the range of 22AWG to 28AWG is OK. Telco uses typically 26AWG. If you don't mind the extra work, you could use round 3 pair cables. It is best to stay with a fixed color to pin number in the jacks throughout the layout to prevent later problems debugging!
We find it best to break up this "backbone" wiring into sections. Each section will be a run of cable connected by male-male 6 conductor cords with RJ12 plugs on each end. This allows the network to be quickly disconnected and isolated for fault-finding or expansion. The Digitrax Universal Panels (UP1, UP2, UP3 & UP5) are connection panels that are very convenient for quick layout hook up. They come in a variety of configurations to suit the needs of most layouts. You just plug in your cables and you are ready to play. Obviously it is cheaper to use 6 conductor dual wall plates and wire them in parallel around the layout. This will take you a little more time but will save money. The main down-side to this is that if any of the cables are disturbed or yanked on, it is very time-consuming to try to repair a "birds nest" of small wires under the layout! The choice is up to the you!
Your LocoNet wiring scheme is very flexible and easy to wire. It was designed to be "plug & play" because we know you would rather spend your time running your trains instead of troubleshooting the wiring. The primary concern really boils down to having a physically secure and maintainable wiring strategy and discipline. The "glow" of low price wire and fixtures quickly fades, as you become the poor individual who has to trouble-shoot a maze of "spaghetti" that was disturbed by someone who tripped over "some wires" under the layout!!
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