It's a bus adapter that's part of a system that *emulates* a RX01 or RX02 controller. It doesn't actually drive a RX01/02 (40-pin connector), nor does it directly drive a Shugart 801-style drive (50-pin connector). What you need is a DSD440 chassis, which has a rather smart Z80-based board in it that converts from the DSD 26-pin connector to the Shugart 50-pin bus.

There were also bus adapters for the Unibus and Omnibus available.