SMD Hard Disks - test-drb@ccmp.vtda.org

13 Nov 2001

On Nov 13, 15:12, Jochen Kunz wrote:
...
  You need a 60 pin flat ribbon cable that goes to the
drives in a bus topology
...
  with the last dive terminated. (Much like SCSI) Then
you need a separate
 24 (26?) pin flat ribbon cable per drive from the controller to each drive.
...
  Should be easy to get the components and crimp the
cables. 
You might get away with ordinary ribbon cable, which usually has a
characteristic impedance around 100-120 ohms, for short distances, but the
A cable is really supposed to be 30 twisted pair ribbon cable (one trade
name
is Twist-n-Flat), characteristic impedance 100 ohms.  It's wired pin 1 to
pin 1 ... pin 60 to pin 60.  The B cable is supposed to be 26-pin flat
shielded cable, with a drain wire, characteristic impedance 130 ohms.  It's
also wired pin-to-pin.

The lengths don't matter, as long as they're within the limits: 35 feet for
the A cable and 50 feet for the B cables.  How useful it is to have the
daisy-chain cable shorter than the radial cables, I don't know :-)

-- 
Pete						Peter Turnbull
						Network Manager
						University of York