Futaba 6FN - Manual (Page 14)

Receiver
WHITE
NiCd Battery
Charging plug
Charger (RX)
The 3P red female connector of the switch harness is used to charge the NR-4C (receiver and servo use NiCd
battery) without removing it from the model.
To charge the NR-4C (receiver and servo NiCd battery) without removing it from the model, set the switch to
the OFF position and connect the 3P red male connector from the charger to the 3P red female connector of
the switch harness.