Omron B2HK series contains keycaps suitable for various switch series including B2H, B2R and B3G series. The name suggestion is that B2H was Omron’s original switch series, and that the keycaps for this series were later used on other switches. In their August 1978 JEE article about B2H, Omron wrote: “The B2H contactless keyboard switch features the B2HK key-top series for its exclusive use.” The 1984 catalogue entry for B3G indicates that B2HK keycaps are also used for B3G switches.
These keycaps appear to be Micro Switch–compatible.
B2HK is divided into a number of sub-types according to function. Based on PRDN 388, the 1978 JEE, Journal of Electronic Engineering article Hall IC Keyboard Switches Become the Leading Type by Yoshikazu Kitao—of which only brief excerpts are available—and the B2H catalogue entry, the following sub-types are known:
|Subtype||Switch type||Form||Legend type||Base colour||Top cover|
|D||LED-illuminated||Cuboid||Film insert||White||Gloss clear|
|F||Square inset stepped||White||Clear|
|G||Lamp-illuminated||Standard truncated||Grey||Gloss clear|
The B3G entry shows conventional tall keycaps marked “形B2HK-A, D, E, F, S, L” which are close enough in form and profile to the keycaps found on keyboard model B2R-84E2L-602. By comparison, Omron keyboards made for FANUC always have low-profile keycaps in a kind of square hat shape. The identity of those keycaps remains a mystery.
Available keycap colours are grey, white, yellow, red, cyan and black. Whether these are permitted for all types is not clear.
Model numbers took the following pattern:
- Sub-type: A, E, F etc (see table above)
- Width in units × 10, rounded to two digits, e.g. 1.75 units is “18”; 1-unit width if omitted
- Variant: 2 = two-level, L = L-type
- Colour: W = white, R = red, Y = yellow, B = black, C = cyan; grey if omitted
The August 1978 JEE article Hall IC Keyboard Switches Become the Leading Type includes the following table of types:
|1.5 unit 2 level||B2HK-A152□||B2HK-E152□|
|1.75 unit 2 level||B2HK-A182□|
|2 unit 2 level||B2HK-A202□||B2HK-E202□|
|3 unit L type||B2HK-A30L□||B2HK-E30L□||B2HK-F30L□|
“2 level” refers to stepped keycaps, where the low portion is entirely to one side of the keycap. (By comparison, the IBM Model F XT keycaps were centre stepped, with a low portion either side of the raised portion.)
“L type” is confusingly defined. A 3-unit L type keycap occupies three keystations in an L arrangement, but is only two keys wide and two keys deep overall. The JEE article includes type B2HK-A30L but also indicates that 30L is not available in type A form!
Omron’s discontinuation notices provide indications of the lifetime of this product range.
|Date of notice:||1989-12-01|
|Date of discontinuation:||1990-02-28|
|Discontinued types:||B2HK-A and B2HK-S double-shot keycaps, excluding the numeric keypad 0–9 keys (形B2HK-A/-Sシリーズのキートップの2色成形（0〜9のテンキーは除く）タイプ)|
The document notes that B2HK-D/-E/-F/-G/-J types are excluded (形B2HK-D/-E/-F/-G/-Jタイプのキートップは除きます。) giving us some indication of the range of options, but no indication of what each of these subseries offered.
|Date of notice:||1992-02-03|
|Date of discontinuation:||1992-03-31|
|Discontinued types:||B2KH series keycaps|