Oriental Tech OK-100M

Oriental Tech OK-100M
FCC ID	IZEOTCOK100M (1991)
Branding	None
Manufacturer	Oriental Tech
Product family	Oriental Tech OK-100 series
Features	Variable weight
Layouts	Asian 101
Keyswitches	Oriental Tech spring-over-membrane
Keycaps	Cylindrical Alps mount double-shot
Interface	XT/AT switchable
Introduced	ca. 1991 (FCC registration)

OK-100M is a progressive-rate spring-over-membrane keyboard in the Oriental Tech OK-100 series.

Description

OK-100M uses double-shot Alps mount Tai-Hao TI series keycaps over sliders. The keyboard is XT/AT switchable.

To cater for both US and European layouts, a separate slider module carries the sliders for the keys to the left of Z/Y: one for US layout (long left shift), and two for European layouts (smaller left shift with an additional key to its right). The underlying membrane has three contact positions accordingly.

According to the box, the OK-100 series was sold in the following layouts: Arabic, Belgian, Canadian, Chinese, Danish, Dutch, French, German, USSR, Italian, Korean, Latin America, Norwegian, Portuguese, Spanish, Swedish, Swiss, UK and US.

Characteristics

The keyboard characteristics vary; the following characteristics have been noted on one OK-100M keyboard, and they may not apply to all keyboards:

Variable weighting

Various switches use longer return springs, to give them more resistance. These include keys such as control and shift — generally, keys around the side and bottom edges. Broadly, these use blue sliders instead of white sliders, but slider colour does not appear to be completely consistent.

The OK-100M leaflet claims 60±20 cN for standard keys, and 90±25 cN for the space bar, with an initial force of 30 cN. The actual feel of the switches is significantly lighter than 60 cN, with a simple coin-stacking test suggesting around 45 cN for the normal keys. One could also presume that all the other heavy keys use the same nominal 90±25 cN switches as space bar.

Different membrane springs

The same keyboard can have both parallel (cylindrical) and flared membrane springs (the springs inside the sliders that press down on the membrane sheets). No reason for this is apparent.