On Thu, Oct 29, 2015 at 1:37 PM, Ben Sinclair <ben at bensinclair.com> wrote:
  I only have one RL02, so I think that cable should
work. I ordered it anyway! 
That cable (BC80M) will work even if you get a second drive.  No
matter how the first drive is attached to the controller, to add a
drive, you remove the terminator from the first drive, add a
drive-to-drive cable between the two drives, then move the terminator
to the second drive.
Can anyone with experience from back in the day comment on why there
is a BC80M?  Why all the controllers didn't just use the flat cable to
a cab kit and a drive-to-drive cable?  Cost?  Length?   EMI reduction
 from running the BC80M into a BA23, etc, and only
pushing shielded 
cable outside the CPU enclosure?  Is the flat-cable-and-cab-kit
pre-FCC only?
  I'll keep an eye out for other controllers, but I
think I will order
 an extender and attempt to debug the one I have. 
It seems to be mostly working, so with luck, it's a single IC, once
you narrow it down.
-ethan