>I've successfully used LK401's on many DECstations (3100,
>5000/133, 5000/150, 5000/200, 5000/240, 5000/260), as well
>as vt220's and vt320's.

Someone once told me that the LK-201 successors (lk-401 &c) were
designed so that they all powerup into LK-201 compatibility mode.
they are plug-compatible wiht LK-201s and can be used as field
replacements for LK-201s on vt220s, vt240s, and Vaxstations.
 
AFAIK the only exception is the LK-501 DeskTopBus keyboard used on the
Personal DECstations. Ted - do you know if DTB was some kind of
external standard, like Apple's ADB, or was it purely a DEC WSE invention?