Straight out of the Spektrum Manual.
1. Q: Which do I turn on first, the transmitter or the receiver?
A: If the receiver is turned on first (except for the AR500, AR6100 and the AR7100 receivers), all servos except
for the throttle will be driven to their preset failsafe positions set during binding. At this time, the throttle
channel doesn’t put out a pulse position preventing the arming of electronic speed controllers or, in the case
of an engine-powered aircraft, the throttle servo remains in its current position. When the transmitter is then
turned on, the transmitter scans the 2.4GHz band and acquires two open channels. Then the receiver that was
previously bound to the transmitter scans the band and finds the GUID (Globally Unique Identifier code) stored
during binding. The system then connects and operates normally.
Note: When using the AR500, AR6100 or the AR7100, if the receiver is turned on first, no output
pulses are sent to any channels.
If the transmitter is turned on first, the transmitter scans the 2.4GHz band and acquires two open channels. When
the receiver (except forAR500, AR6100 and AR7100 receivers) is then turned on for a short period (the time it
takes to connect), all servos except for the throttle are driven to their preset failsafe positions while the throttle
has no output pulse. The receiver scans the 2.4GHz band looking for the previously stored GUID, and when it
locates the specific GUID code and confirms uncorrupted repeatable packet information, the system connects
and normal operation takes place. Typically this takes 2 to 6 seconds.
Cheers