CV29 is assigned a single value which chooses a combination of specific effects:
1. Speed step control.
2. Speed table On or Off.
3. Analog mode conversion On or Off.
4. Normal Direction of Travel (NDOT).
5. 2 digit addressing or 4 digit addressing.
Analog Mode Analog mode conversion is very convenient if you plan to run your Digitrax decoded locomotive on regular DC layouts.
With analog mode conversion enabled, the decoder will automatically begin operating as a DC locomotive when no DCC signal is detected by the decoder.
This means that if you place your Digitrax decoder equipped loco, with analog mode conversion enabled, on a regular DC layout, it will run on the DC layout.
Disabling analog mode conversion can be useful too as the following example illustrates:
Brake Generator Example: If you disable the analog mode conversion feature in a decoder, when DC power is present the locomotive will stop.
This gives you a very inexpensive way of generating a "brake section" for stopping DCC locomotives in front of red signals.
By NOT allowing analog conversion in the decoder, a relay can supply DC voltage to a track section in front of a red signal to slow and stop a locomotive in the brake section.
When the signal turns green, the relay can restore the DCC track signal, and the locomotive will restart.
The decoder will slow to a stop and restart at its programmed deceleration and acceleration values.
In addition, if you are using an FX decoder with CV13 programmed to keep functions running on DC, the loco's lights and functions will remain active when stopped on the DC brake section as long as DC power is supplied to the track while the loco is stopped!
Digitrax does not have a stated policy about using analog mode, but many operators have turned this feature "off" because they feel that it offers more reliable operation.