[Coco] Multipak redesign/replacement / New CoCo...

[RETRO Innovations]

On 2/23/2015 11:42 PM, Gene Heskett wrote:
> 40 wire ribbon is supplied in 25 or 50 foot+ spools, and the connectors are
> all IDC.  The header pins soldered into the board are not that expensive,
> although I would opt for the gold flashed versions of both the header and the
> cable socket to improve the long term connectivity.
Understood, but for signal integrity at the speeds we're talking, the 
crosstalk on the cable is what kills this.  We need cable that is:

GND
signal
GND
signal
...

This is why many IDC flat cable assemblies have all of one side of the 
2x pin header mapped to ground.  So, that's the "shielding" we need.

As I noted earlier, ATA 6 IDE cables were the first thing I considered, 
but they only have 31 IO lines available, and we need 36 at the very least.

Jim

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