DCC in three easy lessons!
plbab,
Basically, the way DCC works is using a "digital" signal. Instead of your controller varying the voltage on your tracks, to make the loco speed up, move along, or stop, you have a constant 12 V DC supplied to the tracks. This does NOT vary.
A computer chip (or your computer) then puts a digital signal across the tracks, that a tiny circuit board in the locos detects and varies the voltage within the loco only, to get it moving along or stop.
Each message generated by the computer chip (or computer) is directed at a specific loco.
If I turn my cab controller "up" to make the loco go faster, instead on increasing the track voltage, it will generate something like this:
44;001;002;003 etc (This is only an example)
The number 44 will be the loco number
001 will be "slow speed"; 002 maybe "turn the lights on", and 003 may be "toot the whistle".
To us DCC (Digital Command Control) you need to put a small circuit board (called a "decoder") in each loco. You also need a "Command Station". and you also need one/more cab controllers. The "Command Station" is plugged onto the tracks, just as your current controller is.
The circuit board in the loco detects and understands the computer "commands" the Command Station generates and puts across the tracks. The cab controllers are plugged into the Command Station, so you can have more than one operator.
Alternatively/additionally, you can plug your computer into the "Command Station" and use your keyboard to control you trains.
It is NOT a cheap system. If you want sound (steam choof choof, or diesel etc). Yes, you can do that, using a little speaker in the loco) you will be up for more than $100 US per loco for the circuit board ("Decoder"). Basic decoders (no sound, just forward reverse, light on/off) cost around $40 per loco.
The Command Station, anywhere between $350 - $500 US for a good one that has all the features. The Cab Controllers, are about $50 - $100 US each.
Prices are, of course, getting cheaper all the time.
Check out the NMRA site for a very detailed explanation of DCC and the "Standards" they have defined.
The good thing about DCC is that it lets you have as many locos as you like on a single piece of track, going in any direction you like at whatever speed you set, because it is the chip inside the loco, that controls it, not the voltage across the tracks.
I use
this site as a base for DCC stuff. It's an OZ site, but I check it regularly for updates etc. I will eventually go DCC, but not right now. Too costly.