Maxxum Lens Connector Pinouts

The original Maxxum connector had five contacts on the right side.
Three more were added with the introduction of Xi cameras and SSM lenses on the left.
The far left two pins are strictly heavy duty power connections and are separate
from the other six which are logic related.

The third pin from the left is possibly the completion of the four wire SPI ie, MOSI.

The arrangement of the logic pins follows modified SPI serial communication.
The original Maxxum 7000 used Mitsubishi serial data bus chips and microporocessor.