Along with the information below, we have provided some easy to use CV calculators for your convenience.

Click here to see the CV Calculators

Digitrax decoders use many different cofiguration variables (CVs) to control the operating characteristics of the decoder.  CV usage is fairly standardized from decoder to decoder but there may be differences in how CVs are used by different manufacturers.  To be absolutely sure about which CVs a particular decoder uses for a particular feature, the range of values available and the factory default value please consult the specification sheet available on each decoder's product page.  This will give you a complete list of CV uses for each individual decoder.

Note that some legacy decoders do not use the same CVs that are currently in standard use.

Click here to use our CV61 Calculator

Digitrax uses CV61 to give you the following features:

1. Non-Directional Headlight Operation
2. Transponding Enabled or Disabled
3. Split Phase Motor Drive for Marklin AC and Lionel Type motors

CV61 is a manufacturer specific configuration variable. 

The look up table below shows the effects of different CV values that you can program into CV61.

The factory default Value for CV61 is 01.

If you would like additional information about these features, please scroll down below the table. 

Non-directional headlight Operation Most Digitrax decoders support the independent control of the head light and tail light. In decoders with this capability, if you don't want automatic reversing headlight operation (the decoder's factory default setting), you can set up the white lead for the headlight to operate on F0 (function 0) and the yellow lead for the rear light to operate independently on F4 (function 4). This lets the engineer have complete manual control over when these lights are on.

Program CV61 to a value of 01 and the decoder will "map" the normal reverse light function lead (yellow) to be controlled by the F4 function key. In addition the normal forward light function lead (white) will become a non-directional light lead that is controlled by the F0 (light function) button on the handheld. If you have set up FX or FX³ operation for the white & yellow leads, this will continue to work. These effects can be made directional by programming an appropriate CV Value.  Program CV61 to a value of 00 and the decoder will return to automatic directional lighting with the white lead being the headlight and the yellow lead being the reverse light. The non-directional headlight feature is not available on Digitrax DN121 decoders.

Transponding Enabled/Disabled Digitrax decoders with transponding are shipped with CV61 programmed to 00 for transponding disabled. Before implementing transponding, you must enable this feature in your decoders. Transponding enabled or disabled does not affect operation on non-transponding layouts.  Transponding lets you know where on the layout specific locomotives are located.  Implementation of transponding requires instrumenting the track and enabling this feature in your decoders.

Split Field/AC Motor Drive When you program CV61 to 04 Digitrax decoders with split field motor drive capabilities will convert their motor leads to drive a "split field " AC motor instead of the default DC motor. This lets you run Marklin 3 pole AC motors and similar motors in a number of locos built in Europe with Digitrax 1.5 amp decoders. For Hi-rail AC motors, you can use Digitrax decoders rated at 3 amps or more. To use an AC motor, connect the common motor/brush to the blue (lamp common) lead on the decoder. Connect the forward field coil to the decoder's gray lead. Connect the reverse field coil to the decoder's orange lead. Be sure that any other mechanical or electrical reversing relay and/or track feeds are removed from the AC motor. The decoder's wires should be the only wires connected to the converted AC motor. Be sure all motor connections are isolated from the motor chassis. Programming decoders set up for AC operation: Once you set up your decoder to run with an AC motor by programming CV61, you must have the motor or a lamp load connected from the blue lamp common wire to one of the motor leads to do any additional programming. You can also connect a 1 k ohm resistor to the blue and gray wires to simulate the AC load to allow additional programming. 

Digitrax decoders are capable of “advanced consisting” where the decoders themselves maintain consist information.

This makes the consists transportable from layout to layout (as long as the locomotives are put back on the track in the same configuration in which they were set up).

Advanced consisting requires that ALL decoders in the consist have decoders that are set up for Advanced Consisting. Most decoders currently on the market have this feature. Non-DCC locomotives cannot be included in an Advanced Consist.

With Advanced Consisting, program an Advanced Consist Address using CV19 and set up how the functions on locos in the consist will work using CV21 & CV22.

Digitrax command stations are capable of universal consisting where the command station maintains consist information. In the case of UniVersal Consisting, the consist is set up in the command station using your throttle. This type of consist can have any DCC decoder equipped locomotive included along with non-DCC locomotives as well.

Customers using Digitrax command stations can use either Advanced Consisting or UniVersal Consisting in operation.

CV19 is the advanced consist address.

CV19 also contains data for the direction in which the consist will operate.

See the table below to determine what value to program into CV19

When CV19 is active, the functions within the advanced consist are individually controlled at their regular addresses.

Click here to use our CV21 & CV22 Calculator

CV21 & CV22 allow you to control specific functions using the advanced consist address.

To determine the value to program into these CVs, add up the values of the functions you want to control in the advanced consist and program that value into the CVs.

To make all functions in an advanced consist be controlled by the advanced consist address, program a value of 255 into both CV21 & CV22.

CV21 Values

CV22 Values

For example: If you want to have F0, F1 and F5 controlled by the advanced consist address, program CV21 to a value of 017/x11 and CV22 to a value of  001/x0. All other functions will still be controlled by the decoder’s regular address.

Decoders with FX³ features have 8 user configurable, independent special effects generators.  These are set up by programming CV values as described below.  All current production Digitrax decoders are FX³ capable.*

FX³ functions incorporate FX generators with additional dynamic and static qualifiers.  FX³ functions are fully mappable so they can be controlled by any function key on your system.  A master light switch can be set up to turn off all lights on a locomotive. Functions associated with advanced consists can be controlled, as well.

Setting Up FX³ Effects On FX³ Function Outputs

Each function output has an associated FX³ control CV. Using the FX³ Generator CVs table below, determine which CV is associated with the output you are using to set up an FX³ effect. For example, if you want to set up an FX³ feature on your forward headlight, you will use CV49 to control the FX³ feature for the led/lamp attached to the F0F decoder output.

Note:  For FX³ decoders, you can set up as many as 8 FX³ function outputs. All FX³ outputs can be set up with FX³ effects.  Many decoders do not have 8 function output wires attached for all functions that are available. See the specific decoder instructions to determine which "pad" on the decoder controls each function. Use thin wire or wire saved during previous decoder installations to solder function output wires to the pads associated with the function you want to use.

FX³ Generator CVs

Each FX³ effect has a CV value that generates the effect you want on a particular output.  That CV Value also controls the FX³ effect’s operating characteristics with respect to locomotive direction and the head light (F0) function.

Use the following two tables to determine the CV value to program for each individual output lead.  Choose a value from the FX³ Effect Table and a value from the FX³ Operational Characteristics Table.  Add these two numbers together to determine the CV value to program into the CV associated with the output you are using to achieve the effect and operational characteristics you want.

For example, if you want a particular function output to remain a simple on/off output, leave it programmed to the factory default of CV Value = 00.  That is from the FX³ Effect Table a value of 0 + from the FX³ Operational Characteristics Table a value of 0 = a CV Value of 00.  This gives No FX³ effect, normal function control of lead, in forward direction the lead will be ON when the function key is ON for that output lead, effect phase A.

FX³ Effect Table

FX³ Operational Characteristics Table

*If your decoder is not a series 3 or later decoder, please check the spec sheet to determine which type of functions it supports.Typically the series number of your decoder is the 3^rd digit in the part number.For example a DH123D is a series 3 decoder (D=DCC Decoder, H=Smallest Scale It Will Fit, 1=1 Amp current rating, 2=Number of function outputs available, 3=Series number, D=Digitrax JST connector to wires interface.)

The tables included in this section will NOT work for older Digitrax decoders with FX function generators.These decoders use different CVs to control their function outputs. Please see the documentation that came with these decoders for information on these CVs and how they work.There is also an article in the Tech Support Depot explaining FX function generators and their associated CVs.CV53 and CV54 are NOT used for FX³ control.

Click here to use our CV62 Calculator

Click here to use our CV63 Calculator

CV62 lets you control the rate and keep-alive brightness for each FX³ effect you set up. The CV value for CV62 is made up of 2 digits, the first digit and the second digit.

The first digit controls the keep alive/baseline off voltage for incandescent lamps. This value should be between 0 and 15. A value of 0 gives no keep alive and a value of 15 gives maximum keep alive. Values between the high and low allow you to vary whether the lamp actually goes off between light pulses or whether it stays on very dimly or more brightly. (If you are using LEDs, the first digit for CV62 should be 0.)

The second digit controls the rate of the FX³ effects programmed. This value should be between 0 and 15. A value of 0 gives a fast rate and a value of F gives a slow rate of operation. We recommend you start with a 4 and adjust it up or down until you get the effect you are looking for.

Ditch Light Hold Over Time CV63

If you are using the ditch light effect in conjunction with F2, CV63 lets you set up a hold over time to control how long the ditch lights continue to blink after F2 turned off by releasing the key on the throttle. Remember that F2 is a momentary key on most Digitrax throttles that will keep function 2 on as long as you hold the key down and then turn function 2 off when you release the key. This allows the ditch lights to be on steady during regular operation and to begin alternate flashing when F2 (usually the horn) is activated and to continue flashing alternately for a predetermined length of time after F2 is released; just like the prototype. A value of 00 yields no hold over time, a value of 40 yields a realistic time of about 5 seconds. A value of 255 yields about 20 seconds hold over time.

Click here to use our Hexadecimal / Decimal Calculator

Decimal and Hexadecimal Numbers For Programming CV Values

Over the years, different Digitrax throttles have used a combination of decimal, modified hexadecimal and hexadecimal numbers for entering CV#s and CV values.

The following information is provided as a programming reference to show you how these different schemes work so that you will be able to use your current production and heritage throttles to program decoders.

Utility Throttles UT1, UT2 & UT4 use decimal numbers exclusively for CV#s and CV values. Because these throttles use 2 selector switches that can access the numbers 0-9, you are limited to programming only CV#s and values from 00 to 99. 

DT300 & DT400 Series Throttles use decimal numbers for entering CV#s and can use either decimal or hex for entering CV Values.  You can change from decimal to hex and vice versa by clicking the R encoder knob when you are in programming mode.  When a hex value is displayed, you will see an “x” in front of the number.  When a decimal number is displayed you will just see the three numbers.

DT100 Throttles use a modified hex numbering system for accessing CV#s and the CV value for the decoder address (CV01) as shown on the following table.The DT100 is limited to programming CV#s 01-128.(See your DS54 manual for special method of programming CVs related to stationary decoders that are above this range.)A 2 digit decoder address can be any decimal number from 01-128.When you use your DT100 throttle to access 2 digit addresses or CV#s, decimal numbers 00 to 99 appear in the display as 01-99 and decimal numbers 100-128 appear as listed below.For example, if want to select address 120 to run on your DT100, dial up C0. 

DT100 Series Throttle Display-CV# & 2 Digit Address

01-99 appears as 01-99Addresses above 99 listed below:

 DT100 Series Throttles use hexadecimal notation for all other CV Values entered.

Decimal to Hexadecimal Conversion Chart

Notice that when using Hex numbers, the 6 and b look very similar in the throttle display so be careful that you are programming the value you want.