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Omron B2C, B2G, B2H, B2R and B2A

Contents

Overview

B2C, B2H, B2R and B2A were Omron’s high end keyboard and switch series. B2R was a reed switch series, while B2H and B2A switches used Hall sensors. Details on B2C are not yet known. The switches share patents and common design elements. Notably, the switches support centre illumination using a novel method of replacing the return spring with a pair of side-by-side internal springs that carry the LED current. Unlike Alps and Cherry designs where the LED is supported on external springs, here the LED springs are internal and support the plunger. It appears that all the switches offer both upstroke and downstroke damping.

At present, very little has been discovered in the way of documentation on any of these series, and both the keyboards and switches are extremely rare. The only type ever observed in a keyboard is B2R, found normally in FANUC keyboards. All these series are long since discontinued.

Background

Some time back in 2016, I came across an unidentifiable Omron switch on AliExpress. The sole photograph was fairly small, and the only identifying mark was the word “OMRON” along the top. At $145 for a lot of ten used switches, they were ridiculously overpriced and I declined to buy them. However, I was extremely intrigued by this unknown Omron switch, and eventually I could not resist temptation any longer, and purchased a lot of ten.

I found out what they were before I received them, because after they were desoldered and shipped domestically within China, another AliExpress seller posted extra photos, where the series name moulded into the switch—B2R—was readable, along with a letter M printed on the side that implied model or part B2R-M. From this I found B2R-G1, a non-keyboard reed switch, and guessed (correctly) that B2R-M was also a reed switch.

Fast forward to June 2018: a patent search on Espacenet for Omron turned up a couple of interesting patents for this family (see under patents below). The patents covered Hall and reed sensing and centre illumination. Since the tall shell is used with both Hall sensors and reed capsules, one could argue that the “R” in “B2R” stands for “reed”. This would suggest that the Hall effect switches would be either B2H (for “Hall”) or B2C (for “contactless”). An Internet search immediately turned up such a switch, for sale over at Yahoo! Japan: B2H-F7W. This switch was in fact the lower-profile, PCB mount–only design also featured in the patents. Blaise Cannon proxied some for me, and I also directed Jacob Alexander to them, and he acquired some and measured one.

Patents and utility models

Utility model JP S5048968 U (“Pushbutton switch”, filed 1973-08-31) depicts a three-terminal magnetically sensed low-profile keyboard switch. The illustrations are crude, but it bears a small resemblance to B2H-F2W.

Utility model JP S5152878 U (“Pushbutton switch”, filed 1974-10-17) depicts some kind of reed arrangement; again, the drawings are too simplistic to understand by themselves. The switch again bears a small resemblance to B2H-F2W.

Patent JP S53136680 A (“Keyboard Switch”, filed 1977-05-04) includes the magnetic click and tactile arrangement, depicted within a lower-profile reed switch.

Patent JP S55105916 A (“Contactless Keyboard Switch”, filed 1979-02-06) appears to cover the Hall sensing option; again, I cannot translate it, and the drawings are unclear, but this time the Hall sensor is marked. This patent depicts a Hall switch identical in shape to B2R (tall, plate-mounted), as well as the design of B2H-F7W (short, cube-shaped and PCB mount only).

Utility model JP S55138721 U (“Keyboard switch”, filed 1979-03-26 ) depicts B2R reed switches.

Patent JP S57136719 A (“Method of Producing Illumination Keyboard Switch”, filed in 1979 or 1982) covers Omron’s centre illumination system using two parallel return springs to support the plunger and supply power to the LED. The Hall IC version is depicted, but I don’t know if that is mentioned. The patent does detail an extra part that appears to be used (based on a translation of a laborious correction of a lousy OCR attempt at a couple of paragraphs) for both alternate action and tactility. The latter may explain what the triangular slot is in the plunger of some B2R switches, but a proper translation is required to be able to determine this.

Series

B2R

All B2R switch types discovered so far are reed switches, using a plastic carrier bearing a reed capsule. They are all fairly tall, with a shell around 15.5 mm tall not including standoffs. The shell and plunger support both tactility and alternate action, but it remains unclear quite how this works, as the patent drawings differ from production B2R switches.

Keyboards are currently known to use the M and ME subtypes. Subtype G is a larger, non-keyboard variety. There is also a variant of M (tentatively B2R-M-T with flat terminals that support threading wires through and solderless installation.

The following switch models are known:

Model For Type
B2R-M Keyboards Momentary
B2R-M1 Momentary
B2R-ME Momentary, LED illuminated
B2R-ME1 Momentary, LED illuminated
B2R-M-T Other Momentary; flat terminals
B2R-G1 Other Momentary

B2R was discontinued at the end of March, 1993.

B2G

B2G is only known as a keyboard series.

B2H

Only one B2H switch model has been found to date, which is a low-profile PCB-mount Hall effect switch. No keyboards have been observed thus far.

Model Type Sensor Output
B2H-F7W Momentary, click tactile, low profile DN837 Current sinking, dual redundant outputs

This is a Hall effect switch, smaller at only 12 mm tall. There is presently no evidence to indicate whether these smaller switches support either non-click tactility or alternate action (both of which were described in a patent for the taller design used with B2R).

The centre digit of the model number (here, 7) may relate to the model of Hall IC used, similar to the apparent arrangement of B2A model numbers.

B2H was discontinued at the end of March, 1990, with B2A-□□2 named as the alternative.

B2HK

B2HK series contains keycaps. The suggestion is that B2H was the original series, and that the keycaps for this series were later used on other switches. The 1984 catalogue entry for B3G series indicates that B2HK keycaps are also used for B3G switches.

B2C

No B2C switches or keyboards have yet been observed.

B2A

B2A is a Hall effect series. No such switches or keyboards have yet been observed. The following subseries are known:

Series Hall sensor Type Introduced Discontinued
B2A-□□7 DN6837 Current sinking 1988
B2A-□□2 DN6852 Current sinking 1988 1993
B2A-□□6 Current sourcing 1990

The final digit of the model number seems to correspond with the final digit of the Hall IC.

See PRDN 784 below for specifications.

B2A was discontinued at the end of March, 1993.

Keyboards

UncleFan came across B2R-84E2L-602: it is an 84-key keyboard. Previously I misinterpreted “キーボード形” as “keyswitch types” but now I see that “switch” does not appear anywhere in the PRDN, and that the list below is all keyboard types. From this we can see what size keyboard each of B2C, B2H and B2R were used in, as well as evidence that there were indeed a lot of keyboards made using these switches.

The “E” might denote “encoded”, since the only types not to have the “E” are B2H-12-219 and B2H-12-336, which appear to be keypads, and these are often not encoded. One keyboard has “Z” instead of “E”.

Discontinuations

Omron’s discontinuation notices provide most of the known data on these series.

PRDN 373

All five discontinued models are dedicated products for specific customers.

キーボード形B2Gシリーズのー部の生産を中止いたします。
(“Production of B2G series keyboards will be discontinued”)
Date of notice: 1987-11-01
Date of discontinuation: 1987-11-01
Discontinued types:
  • B2G-84E2L-327 (replace with B2R-84E2L-602)
  • B2G-49E4L-328 (replace with B2R-49E4L-603)
  • B2G-64E4L-402
  • B2G-76E1L-401N
  • B2G-71Z4L-319

PRDN 374

キーボード形B2Cシリーズのー部を生産中止いたします。
(“Some B2C keyboard models will end production”)
Date of notice: 1987-11-01
Date of discontinuation: 1987-11-01
Discontinued types:
  • B2C-66E4VL-406 (replace with B2C-66E4VL-604)
  • B2C-66E4VL-417 (replace with B2C-66E4VL-604)
  • B2C-16E4L-104 (replace with B2H-16E)
  • B2C-58E2L-103 (replace with B2H-58E2L)
  • B2C-76E1L-102 (replace with B2H-76E1LB

Models B2C-66E4VL-406 and B2C-66E4VL-417 are noted as being for specific customers. For the remaining models, the document notes that the key layout is the same, but there are differences in the parts, thus one should check the specifications. (キーの配列は同じですがー部異なる点がありますので,製作仕様書にて確認ください。)

PRDN 388

キートップ形B2HK-A/-Sシリーズの生産を中止します。
(“Production of B2HK-A/-S series keycaps will be discontinued.”)
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.

PRDN 389

キーボード形B2H-76E1Lその他生産中止のお知らせ
(“Notice of discontinuation of keyboard types including B2H-76E1L”)
Date of notice: 1987-12-01
Date of discontinuation: 1988-02-29
Discontinued types:
  • B2C-66E4VL-604
  • B2C-66E4VL-604B
  • B2C-68E4VL-101-001/002/004/005/006/007/008/009/010
  • B2C-68E4VL-101-011
  • B2C-68E4VL-504
  • B2C-68E4VL-504-002
  • B2H-12-219
  • B2H-12-336
  • B2H-50E2L-225
  • B2H-52E4L-404
  • B2H-58E2L
  • B2H-62E2L-095
  • B2H-62E3VL-017F
  • B2H-62E3VL-150
  • B2H-62E3VL-150C
  • B2H-67E2L-216
  • B2H-69E2L-204
  • B2H-76E1L
  • B2H-78E1L-078
  • B2H-82E4L-178-A2
  • B2H-83E3VL-151
  • B2H-89E2L-234
  • B2H-89E2L-403
  • B2H-91E3VL-155-2
  • B2H-93E4VL-207
  • B2H-93E4VL 206
  • B2H-96E1L
  • B2H-97E4L-353
  • B2H-129E1L-185
  • B2H-133E2L-218
  • B2R-84E2L-602
  • B2R-95E2VL-016

PRDN 524

リードキーボードスイッチ形B2R1-Mの生産を中止します。
(“Production of model B2R1-M reed keyboard switch will be discontinued.”)
Date of notice: 1988-09-01
Date of discontinuation: 1988-09-30
Discontinued types: Reed switch model B2R1-M

PRDN 578

This document notes that (Matsushita’s) DN6837 Hall IC is discontinued, and thus B2A-□□7 subseries is terminating with it. (形B2A□□7シリーズに内蔵のホールIC形DN6837の生産中止にともない新しく形DN6852を内蔵しましま。) A new B2A subseries of B2A-□□2 was created in order to utilise the replacement Hall IC, DN6852. The dimensions and electrical characteristics remain unchanged. (これにともない形式を新たに形B2A-□□2シリーズとします。外形寸法・電気的特性は同ーです。)

無接点キーボードスイッチ形B2A-□□7シリーズの生産を中止します。
(“Production of B2A-□□7 series solid state keyboard switches will be discontinued.”)
Date of notice: 1988-12-01
Date of discontinuation: 1989-01-31
Discontinued types: B2A-□□7 series (replaced by B2A-□□2)

PRDN 649

キーボード形B2Aの生産を中止します。
(“Production of the keyboard type B2A will be discontinued.”)
Date of notice: 1989-04-01
Date of discontinuation: 1989-03-01
Discontinued types: B2A keyboards

PRDN 651

キーボードスイッチ形B2Hの生産を中止します。
(“Production of B2H series keyboard switches will be discontinued.”)
Date of notice: 1989-04-01
Date of discontinuation: 1990-03-31
Discontinued types: B2H series switches are discontinued; B2A-□□2 is to be used instead

PRDN 784

PRDN 784 contains a number of specifications about B2A-□□6 and B2A-□□2.

キーボードスイッチ形B2A-□□6シリーズの生産を中止します。
(“Production of B2A-□□6 series keyboard switches will be discontinued.”)
Date of notice: 1990-02-01
Date of discontinuation: 1990-03-31
Discontinued types: B2A-□□6 series (current sourcing; B2A-□□2 current sinking types to be used instead)

PRDN 1219

キートップ形B2HKシリーズの生産を中止します。
(“Production of B2KH series keycaps will be discontinued.”)
Date of notice: 1992-02-03
Date of discontinuation: 1992-03-31
Discontinued types: B2KH series keycaps

PRDN 1220

キーボードスイッチ形B2Aシリーズの生産を中止します。
(“Production of B2A series keyboard switches will be discontinued.”)
Date of notice: 1992-02-03
Date of discontinuation: 1993-03-31
Discontinued types: B2A switches

PRDN 1221

キーボードスイッチ形B2Rシリーズの生産を中止します。
(“Production of B2R series keyboard switches will be discontinued.”)
Date of notice: 1992-02-03
Date of discontinuation: 1993-03-31
Discontinued types: B2R switches