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Omron B3K series

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Overview

B3K is a series of keyboard switches manufactured by Omron, and originally designed in partnership with Logitech and designated “Romer-G”. The series is notable for being seemingly the first modern (as in, following the general demise of high-end consumer keyboards) computer keyboard switch to be introduced that is not based on an existing switch type (e.g. Cherry MX or Alps/Forward SKBL/SKBM). Romer-G is a significant redesign of mechanical switching, providing a central light pipe for optimal keycap legend illumination and redundant switch contacts.

Omron have since provided versions for other customers, leading to three ranges of B3K switches:

Despite being a dedicated design, the Romer-G switches have not been as well received as it should have been. In particular, the tactile feedback is fairly indistinct. The damping was removed with later models, as that too seems to not have been sufficiently appreciated. No versions presently provide audible feedback.

B3KL series follows B3K and reduces the switch design to a much smaller size, and adds the missing click feedback. Hardware Canucks reported, from their tour of the Omron B3KL production, that re-engineering B3K to offer click feedback would be difficult and expensive, which is why B3KL was designed from the outset to be a click type, such that the click feedback can simply be removed for customers who would prefer not to have it.

Schema

B3K switches are stamped with their part number and batch or lot number. Romer-G switches are widely available to buy through AliExpress and Taobao, allowing these codes to be observed; this is sadly not true of Creative PRES and Das Keyboard Gamma Zulu. Although no official documentation is known for the part numbers, examination of Romer-G switches allowed for part of the schema to be tentatively decoded. José Soltren of Metadot has provided photos of Gamma Zulu; the second “L” in Romer-G part numbers was suspected to stand for “Logitech”, implying that Gamma Zulu would have “M” for Metadot in this position, and this turned out to be the case. Creative refused to provide any information relating to the part numbers of their PRES switches.

The schema is as follows:

B3K-T1DC(2)

The individual positions are suggested to denote the following:

“B3K”
Omron B3K series; the derivation of this is not known, but B may denote pushbutton (reed and Hall types fall under B2x and mechanical types under B3x)
T
Switch type: T: tactile, L: linear
“1”
Unknown; this could denote momentary
D
Travel: 3: 3–3.2 mm, 35: 3.5 mm
C
Customer: T: Logitech, M: Metadot
“2”
Possibly Mk II

The explanation of “3” and “35” (or indeed “13” and “135”) remains a guess. As of 2020, the Logitech website gives 3.2 mm as the travel distance for Romer-G switches, while originally travel was given as 3 mm. No Romer-G switches have the travel distance claimed, which makes verification difficult, but broadly it does appear that the original blue types (B3K-T13L) have less travel than the later models. One explanation could be that the removal of the damping prongs increased travel slightly, and the code remained “3” as the change in travel was not intentional and the rest of the switch remained unaltered.

Known types

Part Customer series Colour Type Pretravel Travel Force Lifetime Notes
Oper. Tactile
B3K-T13L Logitech Romer-G Black/blue/clear Tactile damped 1.5 mm 3 mm 45 gf 70 M
B3K-T13L2 Black/black/clear Tactile 3.2 mm 55 gf Mk II switch, with the damping prongs removed from the mould; factory lubricated
B3K-L13L Black/black/grey Linear N/A Linear version, also without the damping prongs; factory lubricated
B3K-T135M Das Keyboard Gamma Zulu Black/black/clear Tactile 1.5 mm 3.5 mm 45 gf 100 M
Creative PRES ?/extra clear/clear Tactile 1.5 mm 3.5 mm 70 M

See also