Pair both receivers with the DC/DS transmitter in the Double Path mode (or set the backup receiver to CLONE mode). All REX receivers are equipped with fully adjustable inputs E1 and E2. Select for one of these inputs in the settings  EX Bus input/backup (min. irmware version REX 1.13 and REX Assist 1.12). In the main receiver you can set Fail-Safe for servos (we recommend at least lowering the throttle down). In the backup receiver please disable Fail-Safe function and set up the output to EX Bus mode.

 

For the Rsat2 satellite receivers the EX Bus signal is generated at the Ext. output. On the contrary, the Rsat900 receivers are equipped with fully adjustable E1 and E2 outputs.