I think It's 1050 RPM, but I do not use mine. There are lots of experienced B7100 owners around. I sure one will be by shortly to give you a firm answer.
When the engine is running at 2800 RPM:
-the mid PTO turns at 2450 RPM (clockwise frontal view)
-the rear PTO turns at 540 and 850 RPM (clockwise rear view)