SoundTraxx SoundCar Technical Reference - Manual (Page 22)

Tsunami SoundCar Technical Reference Page 20
Primary CVs
EAM (bit 5) must be set to 1 in order to activate extended address capability.
Note that once bit 5 is set, the decoder will respond to commands sent to the
extended address only; commands to the primary address will be ignored.
This can be a problem if you are using a command station that does not
support extended addressing and bit 5 is accidentally programmed. In such a
scenario, connect the decoder to a programming track to access CV 29 and
clear bit 5.
Default Value: 2
Related CVs: CV 12 (Alternate Power Source)
CVs 17 and 18 (Extended Address)