It's easier than that. If you take pretty much any idc connector and put it back to back or hed yo head with another, the end result is the "twist" where pin 1 switches places with pin 40, pin 2 switches places with pin 39, etc.
What I mean by "any idc" is, for instance, a wire-to-board back to back with a male pin header. That makes a Model 102 or 200 cable. http://tandy.wiki/Disk/Video_Interface:_Cable#Cable_supporting_models_102_and_200_only Another form of the same thing is if you put 2 male pin headers back to back, that makes an adapter that can serve as the the twisty part on a cable set that works on all 3 models. http://tandy.wiki/Disk/Video_Interface:_Cable Or head to head: Mike Stein showed me (well everyone) that if you just take any standard 40 pin cables and butt two female ends face to face with a "gender changer" pin header, that results in the same twist. That page above has links to buy all the odd parts for the different ways to do it. But for a pcb to do the switcheroo, the pcb is nothing more than 40 straight lines just to make it easier to solder two plugs back to back. See the "twist adapter" link in that page. You don't have to splice anything to make the cable longer. Just buy or make a bog-standard 40 pin male-female extension cable, and stick it on the DVI end of the cable. They are readily available pre-made and cheap these days in the form of "gpio" cables for arduino or raspberry pi. You can search "male female gpio" or similar on ebay or just pick a length here: http://www.cablesonline.com/240pinidedir.html -- bkw On Thu, Mar 12, 2020, 5:33 PM RETRO Innovations <[email protected]> wrote: > On 3/12/2020 4:17 PM, Mike Stein wrote: > > > Hi Jim, > > I wouldn't call it a newbie mistake ;-) Those 'non-standard' 40-pin DIP > headers have been impossible to find; maybe with your resources you can > find some somewhere so they can just simply be crimped on. > > > I'm wondering if the switch could be made at the other end, with a small > PCB and the respective female header attached to it... > >
