The Hewlett-Packard 9915 computer, an industrial version of the HP 85 computer, was often sold with the option to use an external keyboard, part number 09915-68000, That keyboard, an HP 98155A, was unique to the 9915. I am looking for a second keyboard, so if you have one of these, please drop me a line!

CLOSE-UP PHOTOGRAPHS

Here is a close-up of the left side of the keyboard. Here is a close-up of the right side of the keyboard. Here is a a close-up of the male DB-25 connector. Note that pin 6 is missing (not used).

PATENT

This design is described in US patent 4,460,974.