Looking into this a bit more, I think i have decided to redesign the pendant as well to make it more useful and user friendly.
Attached is a copy of my first attempt. The axis are selected by illuminated pushbuttons at the top, the speed multilplier leds will illuminate when the preset jog wheel speeds are exceeded, enabling the multipliers. The lower 4 buttons are home (axis selected by upper buttons), run, pause and estop.
At the moment I'm thinking of using two 328 arduinos for the logic work, which seems to indicate I would only need a six way cable, which would be light and cheap.
Any thoughts or comments appreciated.
Best Regards
picclock