RL01 and RL02 cables have those funny connectors at both ends. It
sounds like you haven't got the ribbon cable for the interface end
either; that would be a short 40-way ribbon with a Berg connector on
each end with one of the opposite-gender funny RL0x connectors plugged
into one of the Bergs.
I've never seen those connectors elsewhere, but on the inside of the
drive, they're 40-pin headers like a Berg connector, so you could, as a
last resort, use something else to get you going.
The connector on the back of the drive is one of the adapters between the
odd RL-style connector (on the outside) and the 40 pin Berg on the
inside. It is exactly the same part as the connector you put between the
other and of the RL-type cable and the 40 way ribbon cable back to the
controller.
I remember raiding those connectors off scrapped RL power supplies to
connect up the RLs (and for that matter RK07s) in one of my systems.
-tony