I think you misunderstood my question. Of course a UR91 is required to receive the RF signals from a UT4R, DT400R or other Simplex throttle. My question is whether Digitrax Simplex throttles would work with the YD9401 in untethered mode (i.e. whether the YD9401 can properly receive and interpret LocoNet packets coming from the UR91)?
The DR5000 originally could not properly interpret these LocoNet packets, and when a Simplex throttle was unplugged, the slot that it was controlling, and thus the locomotive controlled by that address would behave erratically. Ryan at Iron Planet?Hobbies worked with Digikeijs to find a solution, which was to change the LocoNet baud rate to 800. I don't really understand what this does, but it made Digitrax Simplex throttles work flawlessly with the DR5000.
I know that you never had Simplex over there, as Simplex was about four years gone by the time that the EC?adopted an Implementing Decision to harmonise radio spectrum for short-range devices within the 874-876 and 915-921 MHz frequency bands.