Digitrax Series 3 and later mobile decoders are reset by setting CV08 to a value of 08 to reset everything or 09 to reset every thing EXCEPT the loadable speed table.
Earlier Digitrax decoders require resetting each CV individually.
To reset earlier Digitrax mobile decoders:
Reset your decoder to the factory settings by going into program mode and manually resetting the following CVs to these values:
CV01=03
CV29=06
CV03=00
CV04=00
CV02=00
CV05=00
CV06=00
If you set up loadable speed tables, you may also need to reset
CV65=00
CV66=00
CV67=00
CV68-93=00
CV91=00
CV95=00