Are you still with us? Good. Let's take this a little further with something tangible that you can understand.
The Digitrax system is a Local Area Network architecture that Digitrax calls LocoNet.
There are two parts to the system - the part you can see and the part you can't see.
The part you can't see are the signals that go down the wires. If you read the Big Book of DCC, you will see that the signals go down the wires in the form of "packets". If you are familiar with computer networks, you will recognize what this is right away - it's a LAN. If you don't recognize what this is right away, don't fret. You don't have to know what it's all about -unless you want to get interested in this stuff. In which case, you would join a discussion forum like
loconethackers@yahoogroups.com
Let's deal with the part that you can see - the DT100, DT300, DT400 UT1, UT4 throttles, the UP3 or UP5 panels, telephone jacks, 6-wire telephone cable, male telephone plugs, female telephone jacks. For us non-techie types, this is something we can put our hands on.
Not to confuse things to much, but this physical wiring that we can see - from the throttles to the command station, is usually what's referred to as the LocoNet, notwithstanding that LocoNet also refers to the signals and the protocol that is used to generate these signals. But, as I said, we don't have to know what these signals and the protocols are all about - unless you want to get interested in this stuff (if you are a programmer in Java, Visual Basic and other similar languages, then you might be interested in this stuff).
From the physical point of view, all we have to remember is that the physical part of LocoNet - the part you can see - is a 6-wire standard - 6-wire cable, 6-wire telephone jacks, 6-wire male plugs, 6-wire female jacks, etc, etc.
These 6-wires are colour-coded - white, black, red, green, yellow blue. If you strip open a 6-wire telephone cable, you will see these 6 wires in these 6 colours.
When we connect our components together - assuming we want to get into this aspect of DCC, you just have to make sure that we connect white-to-white, black-to-black, red-to-red, green-to-green, yellow-to-yellow, blue-to-blue. If you're interested in this kind of stuff, then visit this page on my website.
http://www.railwaybob.com/Modules/WiringRJ12s/RJ12s00Index.html
So, in conclusion, I hope we've answered your question - albeit in a very round-about way.
Have fun with DCC. (I am!!!)
Bob M.