Support - Lighting

Overview - Understanding Light Functions

TCS decoders follow the NMRA standards and specifications for lighting functions (Document S-9.1.1), including the color code. The full list of NMRA-standardized wire colors for lighting can be found below, as well as at the previous link.

While it may not make sense on some products without wires, it can be more complicated to define functions as "functions" due to the confusion between sound functions, light functions, and physical buttons on your handset.

To clarify, we like to delineate numerical functions like this:

• A "Button" with a number (0 -> 28) corresponds to the numbered "buttons" on the throttle or other controlling devices. On a physical throttle these would be the numbered buttons on the handheld. Similarly, in JMRI Decoder Pro this is the throttle you can pull up and use from your computer. If you use a cellphone or tablet, these are the buttons you can press on your screen.
• A "Function" is typically defined as an electrical output from a decoder. Sometimes, "functions" can be referred to as "outputs" for better clarity and to limit the confusion with sound functions. Numerals are assigned to each output to distinguish it from the rest. On an 8 function decoder, you have two "0" functions for forward and reverse per the NMRA standard. (0F and 0R count as TWO functions. 2 + 6 = 8)
• A "Function" and a "Button" are NOT required to be linked together. Functions may be assigned to other buttons using the remapping CV's. As an example, for Function 1 and Function 2 these CV's are 35 and 36 respectively. A value of 4 in both of these CV's will remap both of the function outputs to respond on Button 1 on your controller. HOWEVER! A "Function" will ALWAYS retain the same lighting effect CV as its output number. For example, CV51 corresponds to Function 1 and CV52 corresponds to Function 2. Regardless of what button these function outputs are mapped to, their effect CV's will continue to reflect their "Function" number.

TL;DR: "Function" = electrical output from decoder | "Button" = physical numbered button on controller

In the case of a sound decoder, which has both LIGHT functions, as well as SOUND functions, there is an added level of complexity. In this case, we like to use the term "OUTPUT" to refer to a lighting function, and the term "FUNCTION" used to refer to sound operations.

All light functions can be remapped or reprogrammed for your desired operation. For more in-depth details on function remapping and output assignment, continue reading below about Function Remapping.

Decoder Wiring Color Code

The NMRA Standard S-9.1.1 defines DCC decoder wiring colors to be as follows:

NMRA DCC Decoder Wire Color Code

Wire Color	[DCC] Function/Application
Red	Right hand (engineer's side) rail power connection. Could also be the center rail in 3-rail applications, or overhead catenary wire
Black	Left hand (fireman's side) rail power connection. Could also be the outside rails in 3-rail applications, or overhead catenary wire
Orange	Positive (+) polarity Motor connection (for "forward" operation)
Grey	Negative (-) polarity Motor connection (for "forward" operation)
Blue	Common positive (+) voltage source for lighting and other options
Black & White (Striped)‡	Common ground (-) for decoder and/or [lighting] functions
White	Function 0 Forward - Forward Headlight
Yellow	Function 0 Reverse - Reverse Headlight
Green	Function 1 (Output 3)
Violet	Function 2 (Output 4)
Brown†	Function 3 (Output 5)
Pink†	Function 4 (Output 6)
Pink & Purple (Striped)†	Function 5 (Output 7)
Green & Brown (Striped)†	Function 6 (Output 8)

NOTE: This is not a complete chart of all wire colors used by TCS on our decoders. The full chart can be found on the page TCS Wire Color Code.

† "Manufacturers may use any colors or other means to identify each wire such as a tag but each wire must be identifiable and this must be documented in the installation instructions. Black, red, orange, gray or blue of the same shade as the power common may only be used as defined in this table" The colors used by TCS to identify these outputs on all decoders are identified here.

‡ "The wire color for "Ground" may be substituted, but must be documented. All efforts must be taken by the decoder manufacturer so as not to confuse the decoder ground with any other input or output."

Function Remapping

Function mapping of lighting outputs can be done via the programming of Configuration Variables or via Audio Assist on WOWSound decoders. The chart found in the Comprehensive Programming Guide shows the CV's and values that correspond to the function outputs and function buttons. In the DCC standard for packet transmission (that is, the communication over the rails) function buttons for lighting are separated out into two packets, with functions 0-6 being in the first packet, and Functions 7-12 being in the second packet. As such, if a function is going to be assigned to respond to a command in one of these packets, it needs to be configured in that CV. As you see on the chart, Functions 1 - 6 have TWO CV's. The CV on the LEFT of the chart can assign a button from 0 - 6 to that function. A value of ZERO in any of these CV's will disable the function from responding to any button from 0 - 6. Along the RIGHT of the chart are the secondary CV's which correspond to buttons 7-12. By default, these CV's are 0. By programming a value to these CV's, a button or buttons can be assigned to activate the function from 7-12. Note that it is possible to have multiple buttons control the same function using this method if desired. It is suggested that only one CV for each function be programmed with a non-0 value to prevent de-synchronization or confusion.

Along the TOP of the chart are two sections of values from 1 to 128. The numbers from 0 to 12 listed above the values state what value would correspond to that button number. By programming the value listed below a button number, that button will be assigned the function whose CV was just programmed.

It is important to know the difference between a FUNCTION and a BUTTON.

• A FUNCTION corresponds to a numbered function pad or a colored wire from the decoder. For details on which color of wire corresponds to a numbered function output, refer to the NMRA Wires and Connector Standards.
• A BUTTON is located on your throttle or control device and does not necessarily directly correspond to any output from the decoder, as this can be configured.

[Example: You are attempting to move a function to the higher function group. F2 -> Button 8. To do this, once again look at the chart. Function 2 has two CV's - CV36 and CV38. Button 8 is part of the higher functions, which would make use of CV38. Therefore, by selecting the value that corresponds to Button 8 (a value of 8), and programming that value into CV 38, Function 2 will now respond to Button 8. To finish the transfer, we need to clear the button from responding to Button 2. To do this, program CV 36 with 0. Now you are finished!]