Wiring Your Layout with LocoNet
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!!