This is a Maxi-Switch 2160029 keyboard purchased by David Given, purchased surplus in Switzerland. The switches are either Maxi-Switch “vintage linear”. The alternate action switch is identical in design to that of SMK JM-0400 series (including the lubricant used on latching mechanism), making it certain that the two series are directly related.
The part number is 2160029, the PCB code is 630010-11, and the serial number is 016703. The date of manufacture is 1984-10-05, and the controller IC seems to be from the middle of 1983 (the complete date code cannot be read). The controller appears to be an NEC-made Intel 8048.
Tentatively this is a Maxi-Switch MAX-II keyboard designed specifically for personal computers, which appears to be in Maxi-Switch 6000 series, assuming this keyboard is the same one as the Standard-Tastatur MAX-II product leaflet collected from the shop at the same time. (The original MAX keyboard is in 6000 series, and there is a later 6000 series keyboard almost identical to this.)
The leaflet uses “MAX-11” in the manufacturer’s native English, but “MAX-II” where the heading seems to have been replaced by German text. The keyboard is advertised in German as “MAX-II” (replacing the older “MAX-I”) so for the moment, the “MAX-11” is being treated as incompetence.
These photographs were taken by David Given and have been placed into the public domain (CC0).