-PPM Input.
-Not compatible with PWM receivers, needs PPM encoder:
http://store.3drobotics.com/products/ppm-encoder.
-DSM/DSM2/DSMX satellite receiver input compatible: known to work with Spektrum receivers (such as the AR8000) and RC controller such as Spektrum DX7s and DX8. We sell the Spektrum DX7S and DX8.