As of May 24th of 2010, we have a new feature for the FL4 decoders available.
The new feature gives the ability to use opposite dim on all 4 functions. Previously, the opposite dim was only available on function zero which would only work on headlights. To have the Opposite Dim on all 4 functions you need to use CV140 as follow:
Value of one enables function one enables opposite dim on function 1 (F1). Value of two enables function 2 (F2). Values of four enables function 3 (F3). Value of eight enables function 4 (F4)
Value of 16 sets direction of dim for function 1 (F1), value of 32 sets direction for function 2 (F2), value of 64 sets direction for function 3 (F3). Value of 128 sets direction for function 4 (F4).
All of the values can be added to set direction and enable each function.
Dim when Locomotive goes forward (rear light dimed)
F1 . CV140 = 1+16 =17
F2. CV140 = 2+32 = 34
F3. CV140 = 4+64 = 68
F4. CV140 =8+128 = 136
Dim when locomotive goes in reverse. (Front light dimed)
F1. CV140 = 1
F2. CV140 = 2
F3. CV140 = 4
F4. CV140 = 8