I want use encryption on the ULX-D but need a handheld transmitter and a body pack transmitter to work with the same receiver...not at the same time, of course.
There is a firmware update to ULX-D that allows pairing multiple transmitters to a single receiver with encryption enabled. Firmware version 1.4.14 added this functionality.
Go into the Encryption menu and set it to "ON (Manual)." Select this option. The receiver sends the same key to every transmitter rather than generating a new one each time an infrared sync occurs.