I just thought this might help someone.
The RX703A is the Receiver inside a QR X350 Pro it connects to the DADA BUS on the DEVO-M FC.
You can get one for £17 from:-
www.banggood.com/Walkera-QR-X350-Pro-RC-...O-Z-07-p-918378.html
RX703A receiver can talk with all DEVO series transmitter.
Connecting with DJI NAZA Lite or NAZA V2 Flight Controller
On the receiver.
Just use one servo cable to connect DATA BUS port with the X2 port on the NAZA Flight Controller.
Then on the NAZA software choose "PPM" in the RC page, then you control the NAZA Flight Contoller with just one servo cable.
Just like the Futaba S.Bus