Editing IBM Enhanced Keyboard (section)

===Third generation===

The third generation is most commonly associated with Lexmark-made Model M's, indicated most obviously by a change to a blue IBM logo. The primary difference was the addition of a drainage system to direct spilled liquids away from the keyboard's components, and consisting of holes in the case's bottom connected to interior channels in the upper part of the keyboard assembly. For unknown reasons, Greenock-made Enhanced Keyboards had holes but no channels; one theory is that Lexmark made the cases, but IBM produced the keyboard assemblies and did not upgrade their tooling. The lock-light cable was consolidated with the ribbon cable attaching the keyboard membrane to the controller card. While SDL cables were sometimes used, third-generation keyboards usually had a flat, coiled, non-detachable cable.

Third-generation keyboards began appearing in 1992 and continued to be produced until 1999, although by 1996 they had been largely supplanted by fourth-generation models.