Although the UT1 can only handle addresses between 00 and 99, it can be used to operate one four digit locomotive address.
1. On the UT1 dial up 99
2. On a DT100, DT300 or DT400 series throttle, dispatch the four digit address you want to run on the UT1
3. On the UT1 press the ACQ (acquire button) to run the four digit address
Note that dispatching is a special state and the first UT1 throttle to press the Acquire button after the dispatch from another throttle will acquire that address to run.