We have the same problem...

My son took his brand new DX6i to the local club Tuesday night for his first flight. The instructors were unable to get a JLine Quattro to act as a slave. The DX6i ran the servos fine, but when the training switch is pulled there is no response when the Quattro controls are used. The club experts were baffled, even one who had a DX7. Nearly an hour was spent twiddling with the settings (yes, we made sure the timer function was not connected to the training switch). Also, a second buddy box (also a Quattro) and cable were tried with no success.

The manual is unclear as to any settings that may need to be made, and only mentions that if you are using another DX6i, the settings must be the same.

We want to try again this Tuesday. Is there some secret to making this work?