Can a DS64 be powered from the LocoNet RailSync lines?
No. The LocoNet cable is used only for LocoNet commands.
The DS64 must be powered via the rear modular connector (12-14 volts AC or DC) OR via the AUX power 12-16 volts DC using AX1(-) and AX2(+) on the circuit board at the front of the unit. It is also possible for the DS64 to get it's power from the track hooked to Trk A and Trk B terminals, but experience has proven that this power source may not be reliable in certain situations.
NOTE: Use only the rear power jack or the AX1&2 contacts to connect auxiliary power.
Does the DS64 use RailSync for any other purpose?
Yes, the DS64 gets commands from either the track or LocoNet. It automatically defaults to LocoNet if both are present.