From the Feedback module manual...
2.1.4. R/C operation
The DiMAX feedback module is ready to
be retrofitted with the wireless DiMAX
feedback transmitter 8133701 (EU
band) or 8132701 (US band). Firmware
V2.0 is required. All the feedback data
is transmitted to the assigned receiver.
The data from the connected slave modules
will be transmitted as well. For the
wireless operation the feedback module
requires an additional power source of
10…24 Volts AC (e.g. track power).