The behavior of the function / sound buttons on a cab are not defined by the DCC system but rather the decoder in the locomotive. To find out what button does what function, or triggers a certain sound on your locomotive, read the documentation that came with the loco, consult the company's website or contact them by phone.
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Page 27 of the Ph-Pro system Manual / Page 24 of the Power Cab Manual
The behavior of the keys on the Power Cab and Pro Cab cannot be modified. By design the horn key is momentary, all other keys are on/off latching.
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The numbers on the display match the buttons on the cab.
Example: 5 on the display means you pressed the 5 / F5 button on the keypad .
If your locomotive decoder is not programmed to respond to 5 / F5 then it will do nothing.
Current status of Function keys above 6 are not on the normal display. The standard cab display only has enough room to show functions 0 to 6. To see a complete list of all 28 functions use the "EXPN" key - This button toggles the Full Function key display on and off
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Use the regular Keypad to access functions F0 to F9.
EXTENDED FUNCTION CONTROL (F10 - F28)
To access function F13 through F28 hold down the SHIFT key then press the HEADLIGHT (or the 0) KEY once or twice.
Pressing HEADLIGHT will display “F10 through F19 on the bottom line of the cab. Releasing the SHIFT key and pressing a digit will toggle that number plus ten. For example: Pressing 6 will toggle F16, with the display then returning to normal.
The standard cab display only has enough room to show functions 0 to 6. To see a complete list of all 28 functions use the "EXPN" key - This button toggles the Full Function key display on and off
Pressing HEADLIGHT a second time will display “F21 through F28” on the cab. Pressing a digit with this display will toggle that number plus twenty.
Pressing HEADLIGHT a third time will return to the F10 through F19 display.
Pressing Prog/Esc at any time will abort the operation.
If you find holding down the SHIFT key and then pressing HEADLIGHT inconvenient, program the OPTION key to a value of 122 and use the OPTION key instead of SHIFT+HEADLIGHT. Click here to program the Option key
The standard cab display only has enough room to show functions 0 to 6. To see a complete list of all 28 functions use the "EXPN" key - This button toggles the Full Function key display on and off
The answer to your question is not directly related to the NCE system or the NCE cab. All of this is determined. What a loco decoder responds to and HOW it responds is decided by the programming in the decoder. This process as called Button Mapping. It uses CVs “configuration variables” to determine what happens when a loco decoder receives notification that a certain button is pressed. The NCE system does NOT DETERMINE what happens when a locomotive decoder does when it receives a “this button was pressed” notification.
In most cases multiple buttons can be mapped to perform the same function if you use the same CV value in both CVs for both buttons. Please refer to the documentation of the loco decoder.
This is example below is the button mapping details of an NCE DECODER. This is not part of the NCE standard so do not use these values on your decoder unless it is an NCE decoder. This is for an example ONLY.
CV33 F0F default value is 1 output 1 / white / pin 6
CV34 F0R default value is 2 output 2 / yellow / pin 2
CV35 F1 default value is 4 output 3 / green / pin 3
CV36 F2 default value is 8 output 4 / violet
CV37 F3 default value is 16 output 5 / brown or solder pad
CV38 F4 default value is 4 output 6
CV39 F5 default value is 8 output 7
CV40 F6 default value is 16 output 8
CV41 F7 default value is 32 output 9
CV42 F8 default value is 64 output 10
CV43 F9 default value is 16 output 11
CV44 F10 default value is 32 output 12
CV45 F11 default value is 64 output 13
CV46 F12 default value is 128 output 14
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CV67-CV94 Uploadable speed table steps 1-28 (128 speed mode calculates intermediate steps)
CV95 Reverse trim, values 1-127 add to reverse speed, values 129-255 add to forward speed
CV116 Torque kick rate (default is 4)- number of 16ms periods in a row that motor is ‘kicked’ with voltage pulse
CV117 Torque kick strength - how much voltage is used to kick the motor at slow speeds. Reduces
to 0 as speed is increased.
CV118 Ditch light hold time (in ¼ second increments) after F2 goes off.
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CV120 EFX for F0F output 1 / white / pin 6 default value is 1 directional active in Forward
CV121 EFX for F0R output 2 / yellow / pin 2 default value is 2 directional active in Reverse
CV122 EFX for F1 output 3 / green / pin 3 default value is 0 - standard on / off
CV123 EFX for F2 output 4 / violet default value is 0 - standard on / off
CV124 EFX for F3 output 5 / brown default value is 0 - standard on / off
CV125 EFX for F4 output 6 default value is 0 - standard on / off
CV126 EFX for F5 default value is 0 - standard on / off
CV127 EFX for F6 default value is 0 - standard on / off
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