The max for the RB922 is 30V.
Since the RB922 is listed at 17 watts (about 708 ma at 24v) and the R11e is 7 watts (about 291 ma at 24v), you need a minimum of 1 amp (with nothing to spare).
If you're using a standalone power supply, make sure it's at least 1.5A
If you're doing PoE from another device make sure the device can supply 1A on a single port.
Regardless, if you have a long cable, use Cat 6 (23ga wire) instead of Cat 5 (24ga wire) to reduce the current loss.