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Western Digital Systems, Inc., trading as Collimation, Inc., was an American keyboard manufacturer specialising in photoelectric encoder keyboards. Founded on the 26th of June 1972 in Texas, the oldest known advertisement was listed as “Weston Digital Systems Inc.”, presumably misheard in conversation. Western Digital Systems of Texas is not to be confused with the slightly older data storage manufacturer Western Digital Corporation (“WD”) of California. Western Digital Systems traded under the name “Collimation Inc.”, which is the name that appeared in later advertisements.

(Quite which name the company was formed under is not known for certain; OpenCorporates lists the alternative names as “COLLIMATION, INC. (trading name, 1972-06-26 - 1983-01-14)” and “WESTERN DIGITAL SYSTEMS, INC. (trading name, - 1973-04-03)”, indicating that the company had been called Collimation, Inc. from the start. The poor state of business records in general, let alone historical records, makes this unclear. However, Western Digital appears to have been the original name, based on patent filings and advertisements.)

By 1977, Collimation had been acquired by Applied Dynamics International (ADI) of Michigan and was therefore part of the Internatio-Müller Group. ADI themselves traded under the name Collimation Keyboards from 1977–1982, according to the Applied Dynamics International record at OpenCorporates, although by 1977 the Collimation name appears to have been dropped, at least from advertisements. Collimation, Inc. was dissolved in January 1983.


Western Digital Systems only filed a single patent. US patent 3818485 “Keyboard apparatus” was filed in March 1973 under the name “Western Digital Systems, Inc.”; the same patent was filed in Canada in 1974 under the name “Collimation, Inc.” This patent describes their photoelectric encoder design. The name “collimation” itself is derived from the use of a single bulb combined with a curved mirror to produce parallel rays of light across the keyboard. Although this patent was cited on Collimation model D40.592, that keyboard used a separate light source for each channel, specifically LEDs.


An early keyboard from Collimation can be seen under Optical Keyboards on the Robot Less Travelled website, taken from Computer magazine, 1974. Wide space on either side of the keyboard would appear to be there to accommodate the mirrors and horizontal sensor board; the later models were much slimmer due to the use of LEDs as the light source and a simple vertical sensor board.

D40 Series

D40 Series is an ADI designation for photoelectric encoder keyboards with no logic circuitry. Whether this designation pre-dates ADI is unclear, as it is only known from a single 1976 Collimation-branded D40.592 keyboard and that was made around the time that ADI acquired Collimation (between 1975 and 1977, based on the advertisements).


The only known Collimation keyboard models were produced for ISC. D40.59 was a 59-key keyboard made for the ISC Intecolor 8001 intelligent terminal. This was complemented by the 76-key D40.592, a 10-channel D40 series keyboard was produced for the Compucolor 8001 computer and possibly also the Intecolor 8001. The D40.592 unit examined contains three National Semiconductor LM3900 Norton amplifiers dated to early 1976. Unlike the patent design, each of the 10 light channels has its own LED, replacing the single incandescent bulb and mirrors. All the channels fit across a single row, compared to the dual-row design in the patent.

The light source and sensor PCBs within D40.592 support a total of 15 channels, arranged in five groups of three. Between groups of light channels are gaps where the keystem is attached to the shutter. From left to right, the shutters are labelled: ?, C, 6; 5, T, 4; 3, 2, 1; ?, 8, 7; ?, ?, N. “?” denotes positions where all depicted shutters have a notch and no position legend is available for examination. Position 8 correponds to strobe, as its LED and sensor are positioned slightly lower. D40.592 only uses groups 1, 3, 4 and 5, with the first channel in group 1 and the last channel in group 5 omitted (no LED or sensor).

Implementation details on these keyboards are scarce. In a comment in the Y Combinator topic A unusual keyboard key switch, Landon Dyer wrote of the Compucolor 8001 keyboard: “The keyboarding experience was absolutely miserable; you had to COMPLETELY release a key before pressing another. Ghosting and mangled keystrokes were almost impossible to avoid.” The implication here is there was no collision detection at all, something yet to be positively affirmed. A comment from Bill Freiberger under ISC (Intelligent Systems Corp) CompuColor II additional information indicates that these keyboards used BCD encoding. This in conjunction with what little analysis is possible from Jacob Alexander’s very limited set of photographs would suggest that these models did not use constant-weight code to detect collisions, which is the approach taken by Viatron. Further information is expected following operational analysis of a D40.59.


All material scanned by Bitsavers except where otherwise noted.