Master and Slave RC system

Hii,

I am using two skydroid transmitter with pixhawk cube orange plus, for making a trainer drone. I have connected primary receiver in RCIN and secondary receiver to TELEM 2, and changed the serial 2 parameters as required. Both primary and secondary receivers are working fine, but the problem is that when I remove the RCIN connection then only TELEM 2 connection is working.

I need to add button on skydroid T12 to switch to the controls. Please assist me with this.

Why are you using an outdated ArduCopter 4.4. version?

I have submitted my project in this firmware. So, now I am not able to change. If you can help me with master and slave system using skydroid transmitter please help.