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DCC Glossary


Digital Command Control (DCC) is very user friendly and increasingly easy to install. But sometimes the language of the systems alone is enough to discourage some newcomers from giving it a try. While some manufacturers have proprietary systems and names for some of the components of their systems, this list of words is common across them all and covers the core words you'll need to know as you build your own DCC network.


This is the unique number that you assign every cab and decoder on the layout so that it can receive information from the command station. Short addresses are numbers 01-99. Long addresses are 0001-9999. Some systems and decoders can only support a short, or tw0-digit address. Many mobile decoders will give you the option of which you want to use.


The booster takes the command signals from the command station and combines them with the power for distribution around your layout to the decoders. Boosters come in several power sizes and you can use multiple boosters with a single command station for larger layouts.


This is the controller you use to operate your trains and, depending on the cab and system, other DCC-controlled accessories on your layout. Cabs can be hand held or stationary. Some systems offer radio or infrared cabs that do not need to be directly tethered to the layout at all.

Cab Bus

Like the power bus wires used to carry power to your trains, a cab bus is used to connect multiple cabs on your railroad so more than one operator can work at a time. In many systems, this bus is similar to phone cable, with the option of installing multiple plug-in ports around your railroad for “walk-around” control. The cab bus is connected to the command station. To avoid interference, it is best to keep the cab bus at least a few inches away from any of your track power wiring.

Command Station

This is the brain of the DCC System. The Command Station receives data from your cab and other sources on the layout including decoders, occupancy detectors, etc. These data and inputs are converted into digital commands to be sent back to decoders in the trains, switches, etc.


When you want to run more than one locomotive at the same time, in the same train, they can be put together in a consist. *Some systems, like Lionel’s LEGACY command system call this function a “lashup.” This will assign all of the locomotives one temporary consist address. While different systems perform this function in different ways, the end result is generally the same. When programming the consist you’ll need to tell the command station which locomotives are included and which direction they are facing.

CV's (Configuration Variables)

CV’s are Configuration Variables. These little bits allow each decoder to be set to multiple functions. Different CV’s control different things and can be set to either 0 or 1. For example, CV 19 controls the locomotive’s consist. If CV19 is set to “1” then it is in consist mode and will receive commands sent to the consist address. Set CV19 to “0” and the locomotive will respond to its own address. Some functions have more than an on/off option – these must be programmed through multiple CV’s. Since there are differences between decoders and systems for programming, refer to your system’s specific manual for programming instructions.

"DCC Ready"

DCC Ready, or sometimes called “Friendly” by different manufacturers indicates that a product is either ready to use with a DCC system, or easily adapted to it. For model locomotives this usually means that there is a DCC plug pre-wired into the locomotive so a decoder can be installed without any additional wiring. DCC Friendly switches will have properly insulated frogs, points and throw-bars to prevent momentary shorts when in operation.


Decoders receive commands from the command station and convert that code into an action. These must be installed in everything that you want to operate with your DCC system. Stationary decoders are used for things like switch machines that require only a few commands. Mobile decoders are used in locomotives and have many more options, depending on the decoder.


Detection modules are used to gather information for the command station or other devices. Block detection modules for example can tell the system if a section of track is occupied.
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