Hi-Tek “High Profile”
“High Profile” is a retronym for Hi-Tek Corporation’s original switch grid system, for which Hi-Tek had not assigned a name until the DIN-compliant Series 725 was introduced. It was superseded by Dovetail Series. The term “Standard Profile” has also been used.
Hi-Tek High Profile is covered by US patent 3751618 “Push-switch with spring biased plunger”, filed in February 1972 and granted in August 1973.
The design was copied wholesale by Stackpole, leading to great difficulty in identifying whether a specific keyboard uses Hi-Tek or Stackpole switch grids, or a mixture of both (as found in an HP 9825A keyboard).
Branding on Hi-Tek–made keyboards is fairly uncommon. Hi-Tek often supplied only the switch array; where they also supplied the PCB, this was typically branded, as with Hi-Tek keyboard 373-70229B. The Exidy Sorcerer II keyboard bears the Hi-Tek logo, location and patent number on the array frame itself.
The service manual for the HP 85 contains the only official description so far of any means to distinguish the two products. The differences are as follows:
|Component||Hi-Tek form||Stackpole form|
|Contacts||One solid, one slotted||Both contacts identical|
|Spring, standard||28 mm (1.1″)||22 mm (0.89″)|
|Spring, space and alt. action||35 mm (1.4″)||26 mm (1.01″)|
There are at least two variants of the HP 9825 keyboard:
Unfortunately the details for these keyboards are not given in the service manual. The HP 9825 is a couple of years older than the HP 85, which may explain why the former has Stackpole switches that appear to have been directly copied from Hi-Tek, while the latter has Stackpole’s own patented design.
See Hi-Tek and Stackpole recognition on the Deskthority wiki for more details on differentiating the two product ranges.
Very little in the way of models is known. Of the two known models, the scope of the model number is not clear. The IMSAI IKB-1 has an IMSAI PCB, suggesting that “DS6300” represents only the switch array and its keycaps. In the case of the TRS-80 Model I, the PCB is Hi-Tek branded (both PCBs in units with the numeric keypad fitted); whether the PCB was included within model DS5300 is not known.
|DS5300||53-key array in the TRS-80 Model I, with two-shot keycaps (see TRS-80 Technical Manual page 33, 1978)|
|DS6300||63-key array in the IMSAI IKB-1, with custom keycaps; attributed to “Hytek”|
Some DEC VT100 keyboards have a grid moulded by Tontec International (the completed switch assembly being depicted on their advertising image on globalsources.com). Tontec reported that the moulds were returned to DEC after keyboard production ended.