TCS Decoder CV Settings

For suggested general CV settings for decoders from a variety of manufacturers for ready-to-run 4mm/HO/OO locos click here. To purchase TCS decoders, click here.

CVs that are common to decoders from all manufacturers complying with the NMRA standards are shown in italics, others are specific to TCS decoders.


CV No.	Default Value	Description
CV1	3	Primary loco address. 1-127 valid addresses.
CV2	0	Start Volts. Voltage level added to all speed steps. 1-255 valid values. 1 count = 39% of full voltage. For most conditions with TCS decoders leave this as 0 and use Dither.
CV3	0	Acceleration Rate. Adds time to each speed step. 1-255 valid values. Practical range is 0-25.
CV4	0	Deceleration Rate. Adds time to each speed step. 1-255 valid values. Practical range is 0-25.
CV5	0	Vhigh. 1 volt = approx.18. Use this to set maximum speed. Max value is 255.
CV6	0	Mid Volts. Assigns voltage level to speed step 7 when using 14 speed step or to speed step 14 when using 28 speed steps. This generates a performance curve. If CV6 = 0 then Mid volts is not used to generate speed curve.
CV7		Decoder Version Identification.
CV8	153	Manufacturer ID Number. TCS ID Number is 99 hex, 153 decimal. To reset the decoder enter a value of 2 into this CV, then power off and then on. For more details on how to reset a decoder see the additional notes below on Resetting to Factory Default.
CV17	0	Extended Address. Used for 4-digit addressing. Contains upper byte value of address. Bits 0-5 are used for upper 6 bits of 14 bit address.
CV18	0	Extended Address. Used for 4-digit addressing. Contains lower byte value of 14 bit address. Note* CV17 and CV18 are programmed separately but the decoder uses them to form one address. Bit 5 of CV29 needs to be programmed in order to use the extended programming values in CVs 17 and 18. Most DCC systems do the CV17/18 calculations for you when you are programming the loco address provided that you have selected extended (or long) address.
CV19	0	Consist Address. Decoder will respond to this address when this CV is not = 0. Valid values are 1-127.
CV22	0	Consist function Control: Bit 0 is used for FL(f) which is forward head light. Bit 1 is used for FL(r) which is reverse headlight. When these bits = 1, headlight control is under consist control when consisting.
CV29	6	Loco Configuration (decimal values in red): Bit 0 controls loco direction:0 (0)= normal, 1(1) = reversed. Bit 1 sets headlight control and number of speed steps to advanced or standard mode. 1 (2) = advanced (28/128), 0 (0) = standard (14). Bit 2 is to enable or disable analog conversion mode. 0 (0)= disabled, 1 (4)= DC enabled Bit 3 reserved for Railcom enabled decoders. 0 (0)= disabled, 1 (8)= Railcom enabled Bit 4 activates or de-activates user loadable speed table, (CV66-CV95). 1 (16) = table active, 0 (0) = table de-active Bit 5 activates or de-activates extended addressing. If this bit = 1 (32) and CV19 = 0 then loco will respond to address in CV17 & CV18. If this bit = 0 (0) and CV19 = 0 then loco responds to its primary address. Bit 6 and 7 not used. Note*: To calculate the decimal value for CV29 for programming purposes, choose one red value for each active bit and sum the values. The default value of CV29 is 6 to enable 128 speed step and DC/DCC operation.
CV30	0	To reset factory default settings enter a value of 2 into CV30. For more details on how to reset a decoder see the additional notes below on Resetting to Factory Default.
CV49-52 49 50 51 52	0 16 32 32	Special lighting effects control. The value in these CVs determines what lighting effects are selected for a particular function output. It also qualifies it for what direction or condition to turn it on. Factory default is CV49 (White wire)=00, CV50 (Yellow wire)=10hex. This sets up auto reversing headlight operation. See More Information about CV 49 and CV 50.
CV56-57 56 57	0 0	CV56, CV57 Set Dither parameters. See Dither. The default setting for CV 57 on decoders with BEMF is 0, which means dither is off.
CV58	50	This CV is used to enable Kick Start, in conjunction with CV65. It controls the Burst Duration, with higher values increasing the duration. 60 = 1 sec. This function is superseded by the Dither facility of TCS decoders .
CV59- 60	0	Used to customize Mars and Gyra light modulation and latency. For more information on this go to More information about CV59 - CV61. CV56, CV57 Set Dither parameters. See Dither.
CV61	54	Configures additional loco parameters: Bit 0 = enables light functions in analog mode with analog mode disabled. This enables head light to remain on when loco enters a control block with strait dc voltage with the loco stopped when analog mode is disabled. on the new decoders with BEMF, BEMF is enabled if CV61 = 1 Bit 4 = 1 (16) dims the light when stopped Bit 5 = 1 (32) enables opposite dim. When going forward, reverse light is on dim. Vice versa for going reverse. Default = 0 Example: On the new T1 with BEMF to set BEMF on and light dims when stopped and opposite light is dimmed set CV61 to 49.
CV64	64	This provides a brightness adjustment or "adjustable dim" feature when using Opposite Dim or Rule 17 and is a feature available in X series decoders. Useable values are 2-30. A value of 16 = 50% for incandescent bulbs, whilst values of 2-6 work well with LEDs.
CV65	0	This is used in conjunction with CV58 to control Kick Start. Higher values increase voltage, a value of 18 = approx. 1 volt. A value of 0 in CV65 is the default, as Kick Start is superseded in TCS decoders by Dither.
CV67-94		User Loadable Speed Table. This is activated by setting CV29 bit 4 to on. Values 1-255 valid.
CV105, CV106	0	User ID. Can be used to designate your own equipment. 1-255 valid.
CV117		Adjustable ditch lights blink rate. 1-12 valid (12 is the fastest rate).
CV133		Button control of motor. 0-255 valid. Sets the power applied to the motor when the motor circuit is used in button control mode.

Last updated 21 January, 2010

More information about CV59 - CV61

More about CV59

Effects modulation frequency of Mars and Gyra light. The lower the value the faster the frequency becomes. Factory set to 2Ehex, 46dec.

More about CV60

Effects time between light modulations for Mars and Gyra light. The lower the value the less time between modulations. Try setting this to a value of 0Chex, 12dec for Mars light. It is factory set to 36hex, 54dec for Gyra light. Try experimenting with CV59 and CV60 to customize the look of the Mars or Gyra light. Mars and Gyra lighting cannot be operated simultaneously.

More about CV61 options
Setting bit 0 = 1 will re map function 0 rear headlight control to function 4 control. Not applicable with version 16 and up decoders which use function re map.
Setting bit 3 will enable headlight functions to remain on in analog mode even with analog mode not enabled (via bit 3 of CV29.) The advantage is when using straight DC voltage to make a stop block for control purpose, the lights will remain on when the loco is in the stop block.
Setting bit 5 enables opposite dim. The headlight opposite the direction of travel comes on dim (50% power).

Other notes

When the decoder receives a broadcast stop signal the headlights will remain on in the direction they had before receiving the broadcast stop signal.

Resetting CV'S to their factory default

On the programming track ONLY, write a value of two into CV8 or CV30. The decoder must go through a power off then power up, except the A1X, which will reset itself automatically. CV'S will then reset to the factory default values on power up.
Note: writing to CV8 does not actually change the value in CV8 because it is a read only register. When writing a two into CV8 it actually will write to CV30. This enables a factory reset with command stations that use physical register programming like the MRC 2000 and Atlas Commander. CVs that will be reset to the factory default are: 1, 2, 3, 4, 5, 6, 17, 18, 19, 29, 30, 49,50, 61. The user loadable speed table is not effected by the reset to default values.

Optional lighting effects for the head light and reverse light:

CV49 controls lighting effect and directional qualifier for forward headlight (White wire).
CV50 controls lighting effect and directional qualifier for reverse light (Yellow wire).

Use the following two tables to assign a lighting effect:

Each CV uses two digits. The upper digit (MSB) is used as a directional qualifier. The lower digit (LSB) determines the lighting effect. The numbers are Hexadecimal. Example for forward headlight: CV49=08hex, rule 17 applied. CV49=06 hex, rotary beacon on when loco going forward. CV49=14hex, single pulse strobe when loco reversed.

Examples for reverse light: CV50=25hex, double pulse strobe on all the time. CV50=13hex, flashing light when loco reversed. Note: If your command station uses decimal numbers you will have to convert from hexadecimal to decimal.

For a hexadecimal to decimal conversion table click here

Upper Digit Value	Qualifier for direction or condition
0xh	Function is on when locomotive is going forward
1xh	Function is on when locomotive is in reverse
2xh	No qualifier, normal on / off control
3xh	No qualifier, normal on / off control
4xh	Function is on when locomotive is going forward and Fleet Lighter is on
5xh	Function is on when locomotive is in reverse and Fleet Lighter is on

Lower Digit Value	Lighting Effect
x0h	No effect. Normal on / off control
x1h	Random Flicker (fire box)
x2h	Mars
x3h	Flashing Light
x4h	Single Pulse Strobe
x5h	Double Pulse Strobe
x6h	Rotary Beacon
x7h	Gyra Light
x8h	Rule 17
x9h	No effect. Normal on / off control
xAh	Blinking Ditch Light A
xBh	Blinking Ditch Light B
xCh	Dim (applies 50% power to function)

Factory settings: CV49= 00hex, CV50= 10hex. Decimal equivalent: CV49=0, CV50=16. This default sets up auto reversing headlights.

To remap yellow wire (FO) to button 1. Set CV34=4.

To set up Blinking Ditch Lights

Green wire (F1) used for one ditch light. Violet wire (F2) used for other ditch light.
Set: CV51=42 ditch light phase A CV52=43 ditch light phase B
CV36= 4 remap violet wire to button 1
Button 1 now turns off/on both lights. Then use button 2 or 5 to control blinking.

To set up rotary beacon

If using a T4/T6 decoder, use brown wire (F3) to beacon. Set CV53=38.

To set up manual control of headlights

White wire (F0) used for front head light. Set CV49=32.
Yellow (F0) wire used for rear light. Set CV50=32.

To set up auto reversing headlights

Set CV49=0. Set CV50=16.

To set up Gyra light for white wire headlight control

Set CV49=39, or for forward directional qualifier set CV49=7.

To set a light to manual non directionally qualified control

Set the required CV to 32.