When using your transmitter with a simulator, the transmitter is acting the same as when you use it as a "Buddy Box".I have never heard of anyone causing damage to their radio by using it as a "Buddy Box". The futaba and Hitec "trainer Cords" short out two pins on the trainer socket, disabling the rf output (preventing the situation described). In my humble opinion "If the interface fails to make use of the provisions for disabling the fr output(and thereby preventing possible damage to the transmitter) it's design is faulty".