generally speaking (not sure exactly about trane) but most transducers work on 4 to 20 milliamp signal back to the controller (or in Tranes case a board). This 4 to 20 milliamp is matched to the cfms in the program. Example: if you are at 0 cfms your signal back to the board will be 4 milliamps. If max cfms for that transducer is 500 cfms then you will get 20 milliamps at 500 cfms. One wire feeds a voltage (usually 24 vdc)to the transducer and the other wire feeds the milliamp signal back to the input on the controller or board.
Stats??? you have to identify the wires from the technical documents and remember not all stats are fed with voltage.