Here is what is to be done inside the trainer transmitter.
Find the NE5044 IC:
Pin 8 = Ground, connect to shield of cable
Pin 16 = +V connect to RED wire in cable
Pin 11 = Signal connect to GATE of a N-FET via 180 Ohm and 1k pullup resistor
If you dont use the 180 Ohm series resistor the output of the NE5044 will oscillate due to the hight capacitive load of the FET.
Any N-FET will work, I use a IRF740
Source of the FET is connected to ground.
Drain is PPM signal connected to the MASTER EVO transmitter, the evo has internal pullup so no need to add that.
REMOVE battery from trainer transmitter, to be sure it is maybe a good idea to cut the wire inside it.
The trainer transmitter is now powered directly from the EVO master transmitter.
REMOVE XTAL, this will disable the transmitter, and reduce the current usage.
I have also cut the charge diode and removed powersuply to the oscillator, buffer, driver stages, and LEDS has been disconnected.
Here it has been made, trainer cable uses the antenna hole and is glued.
The channels transmitted from trainer is defined as channel 1 first then 2 and 3 and so on.
Here all 3 channels are at center position = 1.6mS each pulse time.
You can make the trainer controll ailerons and elevator only if you like.
The Evo will even trim and remember trims on the trainer !
The EVO switch is intelegent, so it automaticly switches trainer off if cable falls out.
Remember the Servo - Monitor only works with trainer signals, if EVO is in RF transmit mode !
more info in the Royal Evo Manual at page 92 and page 93