Quoting Simon Hobson (linux@???):

[PS/2 6-pin mini-DIN vs. old 5-pin DIN]

> AFAIK the underlying protocol for the keyboard is the same (or near
> enough for simple conversion) between the two connector formats to
> allow for easy conversion between plugs.

It absolutely is, and therefore the two share the trait that users can
(rarely) fry motherboard circuity by assuming the connection supports
hotplug operation, which strictly speaking it was not designed to do.