D4R-II vs X4R-SB - What's the Difference?!

The D4R-II and the X4R-SB look physically the same, but they have some similarities and many more differences. At a very high level, the D4R-II is a PPM receiver while the X4R-SB is a SBUS receiver. One thing I didn't mention is that the X4R-SB has an RSSI output pad that would require soldering... but it does have it. It is pointed out in the manual (link below). ==================================================== You can get one for yourself here: FrSky D4R-II: http://www.banggood.com/FrSky-D4RII-2... FrSky X4R-SB: http://www.banggood.com/FrSky-X4RSB-3... ==================================================== D4R-II Manual: http://www.hobbyking.com/hobbyking/st... X4R-SB Manual: http://img.banggood.com/images/upload...