Comptec was an international manufacturer with a highly successful line of injection-moulded keycaps. Following a management buyout, the keycap division of Comptec in Custer, Washington, United States became Signature Plastics.
Official details are few and far between. US patent 5197178 “Sealed computer terminal keyboard” filed by Tektronix in 1990 refers on column 4 lines 47–50 to a “Tektronix-made, DEC VT100-compatible keyboard with COMPTEC key caps”.
Signature Plastics noted on their website that the SS family was introduced in the early years of Comptec’s keycap production, and has since been retired. SS family introduced sculptured row profiles, while keeping the spherical top profile of the original SA family. A diagram of unknown origin was posted to the Deskthority topic keycap profile demonstration props that shows the row profiles of SS.
There is a mystery keycap series found in most BBC Microcomputer keyboards as well as 10ko’s SAGEM TX-20 keyboard. These keycaps have a stepped internal structure common to Comptec designs, and the six mould ejection witness marks as with other Comptec families. Signature Plastics deny that these keycaps originated from them, but the resemblances are too close to ignore, and no other keycap families are known to follow this overall design so closely. The mystery series is more cheaply made than SS, and DCS is in turn cheaper still.
The BBC Micro keycaps have a stepped profile, but the row profile matches the size and shape of the middle row of SS family. The TX-20 keycaps are uniform profile like SA, which does not match the SS chart, although it is not impossible that SS also contained a uniform profile variation; no catalogues or brochures are known for any of these families.
The following equipment uses keycaps matching this design:
- Acorn BBC Microcomputer (Wong’s/Futaba, Wong’s/SMK and PED keyboards) (stepped profile)
- Some SAGEM TX-20 keyboard examples (flat profile)
- Intelligent Systems Corp Intecolor 101894 (flat profile)
- The Origin of SP Keycap Families – Signature Plastics
- Signature Plastics on the Deskthority wiki