HP 9835 Cherry keyboard
Cherry part B21E-A601 is a custom assembly made for Hewlett-Packard for the 9835 computers. HP’s own reference number is 3101-0436-1 REV.G. This keyboard is significant in allowing the link between Datanetics DC-60 and Cherry M1 (or M11) to be traced.
The serial number suggests that it was made in 1982, or maybe 1983 (see the master vintage Cherry keyboards list).
These photos are from a personal listing at 闲鱼.淘宝二手, specifically id=606580179632, now only available to logged-in users (available publicly when UncleFan first showed me the page, and he saved the images for me). As these images are sure to be deleted before too long, they are preserved here for their importance.