DZ121 Configurable Strobe Lights

The DZ121 is one of the smallest decoders on the market. In order to build a decoder of this size, a very small CPU was used. As we all know, the smaller you make things the less stuff you can fit in. We had to make some decisions about which features to include in the DZ121 because of limited code space.

Transponding was included in the DZ121 because these decoders will be installed in the smallest locos where there isn't any extra room for a separate transponder. We feel that transponding is the next step forward in layout control and we didn't want to deprive anyone of the ability to implement it on their layout.

Scaleable speed stabilization was included in the DZ121 because we feel that it can be a valuable tool for low end speed control when implemented properly and adjusted by observation for the particular locomotive used.

Because of these two new features, code space was at a real premium in this decoder. We really wanted to offer full FX lighting effects but there was barely enough room left to have simple reversing headlights. We decided to remove direct mode programming to save a little code space. The DZ121 supports: Paged, physical register & operations mode programming but NOT direct mode programming. This still didn't leave enough room for full FX lighting functions. There was enough for configurable strobe lighting.

Even though configurable strobes don't use the sophisticated algorithms that FX does, you can do a reasonable job of simulating many lighting effects with them. You should be able to get results at least as good as anything else out there for lighting.

Configurable strobes are controlled with CV49 & CV50.

CV49 controls the White Lead

CV50 controls the Yellow Lead

The value programmed for each CV consists of 2 digits

The first digit controls the conditions under which the light will be active

1x=Reverse, if 1 is the first digit then the light will be on when the locomotive is in reverse

2x=F0 Qualified, if 2 is the first digit then the function will be active when F0 is on and off when F0 is off

4x=Direction insensitive, if 4 is the first digit then the function will be On in either direction

The second digit controls the blinking of the light (AJ calls this blinky lights because it's not FX but at least the lights blink).

x1 Simulated Random Flicker

x2 Simulated Mars Light

x3 Blinking Headlight

x4 Single Pulse Strobe

x5 Double Pulse Strobe

x6 Simulated Rotary Beacon

For example if you program CV49 to a value of 46, the light on the white lead will be on no matter what direction the loco is traveling and will be blinking similar to a rotary beacon.

Experiment and ENJOY!