There is a lot of detailed information on the technical aspects of DCC. I'll add pointers to some of the ones I like best at the end of this article. My goal is to give a very practical explanation at a user level, aimed at what an S operator needs to know. This article is written with the Lenz DCC system in mind, and will use Lenz examples. It is generally applicable to any DCC system, but details will vary. I welcome comments, questions, complaints and corrections.
At the highest level, a standard DCC system is made up of a few devices:
A user input device, usually called a "handheld", throttle, or cab, which the operator uses to run his train. It has knobs and/or buttons to control speed, and buttons to turn on lights, blow the whistle, etc. There can be, and usually are, multiple cabs to allow multiple operators.
A Command Station. This is the device that accepts commands from the operator(s) and converts them into coded signals that are sent to the locomotives (or other things) that we want to control. It is the "brains" of the system. There is only one command station for a layout.
A Power Station (also called a "Booster". The Power Station takes the coded signal from the Command Station, adds track power to it, and puts it on the track. There can be multiple boosters if required to supply enough current for a large layout. The power station and command station need a power supply, normally a 16V-18V 5-8 Amp AC supply, depending on the power output of the power station.
And decoders (also called receivers) in anything you want DCC to control. The decoder in a locomotive is connected to track power through the loco pickups. The decoder looks at the coded signal on the track, and does what it is told: forward direction 15% speed, Headlight on, blow horn, etc. Typically there is one decoder in each locomotive on the layout. Each decoder has an "address", known by the command station. Thus decoder 1 can be told to go forward at 40% at the same time decoder 2 is told to go reverse 10%.
Many DCC Command Stations include a power station in the same enclosure, and that is the case with the current Lenz LZV100. It is a command station with a built in 5 Amp power station or booster. The standard handheld cab for the Lenz is the LH-100, which plugs into the LZV100. Add a 16V power supply or transformer, connect 2 wires to the track, and you are ready to go!
What do I need to get started?