Expander Modules, Part I

Expander modules (digital ranks in a box) such as the Ahlborn Archive series (photo) have in the past been added to and interfaced with an existing digi organ to augment the number of voices available and possibly upgrade its sound.
There aren't many expander modules in circulation any more as their production tended to compete with sales of whole digi organs in the production lines of the same manufacturers; today they're almost non-existent, just about ALL OF THEM went out of production around 2007, and what basically killed the market for them was the arrival of the VPO [See blog, Virtual Pipe Organ (VPO)].
When additional stops are desired, one doesn't mind making a cast outlay for a pre-owned unit of older generation technology, and a VPO conversion of an existing digi console is neither practical nor desired, an Archive module someone is willing to part with, provided one can be located, could be a possible solution.
(con't in Part II)