3 Jan
2014
3 Jan
'14
6:35 p.m.
On 01/03/2014 05:03 PM, Mark J. Blair wrote:
Speaking of cables, I'm going to need to make a
pair of 50 conductor
ribbon cables to connect my Kennedy 9610 drive to my PDP-11/44. It
uses the common Pertec interface, and the cables will need to be many
feet long to allow the tape drive or PDP-11/44 to slide out of the
rack. The original cables were shielded, and the tape drive manual
says that was for EMI compliance. I wonder if I will be able to get
away with unshielded cables, since new 50-conductor shielded ribbon
cable isn't cheap.
You should be--the connections on the standard 2x50 conductor Pertec
cable is that with the exception of a couple of lines on P2, ground
lines are interleaved between signal conductors. I run 10 foot/3 m
cables off of my drives with no problems at all.
If you're worried about shielding, just invest in a roll of aluminum
foil HVAC tape and stick to the ribbon cable. Overlap at the tape edges.
--Chuck