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Controls Research Corp



Controls Research Corporation (CRC) is a very poorly-understood company. Examples of their keyboards and switches are extremely rare. Two keyboard examples have been found, as has one calculator example. Additionally, a bare keypad has been found.


Mark II

The CRC Mark II keyboard was a bespoke keyboard arrangement built around CRC 02 discrete snap-action dry reed switches.

The Mark II keyboards brochure (see Documentation, below) indicates that there are patents pending, but no US patents for Controls Research Corporation seem to have been digitised. Sadly the brochure gives no indication of its age.


TTY37 is a keyboard aimed at the communications market. It offers N-key rollover: encoded key outputs are issued in the same order that keys were struck. Model TTY37 was advertised in Electronic Design magazine in May 1971, with few details given.

Model 7100

Model 7100 is a 53-key MOS-encoded quad-mode keyboard with matrix scanning that uses BI-PAC switches. Power consumption is given as 300 mA. Model 7100 was advertised in Electronic Engineer and Electronic Design magazines in October 1972, with few details given.


SC-6000 is stated to be a 53-key model of C-Scan capacitive keyboard. It is ASR-33 layout with N-key rollover with ASCII output. This model was mentioned briefly in Electronics magazine in December 1973.


CRC 02

CRC 02 is a tall discrete reed switch module offered with CRC’s Mark II keyboards. These switches were advertised as having “magnetic snap action”. The design is fairly tall, measuring 2.025 inches from the centre of the switch base to the top of the keycap. The top of the switch body is 1.25 inches from the PCB, measured from the centre of the base. The base of the switch is angled to 10° to provide a stepped profile when the PCB itself is angled likewise. Switches are secured to the PCB using a pair of 2-56 machine screws.

The switch is illustrated in the brochure as follows:

The switch specifications are as follows:

Travel 0.156″ (around 3.96 mm)
Return force 1 oz (around 28 g)
Snap force 3 oz (85 g)
Contact life 1 million cycles
Bounce time 0.5 ms
Voltage 40 V maximum
Current 50 mA maximum

The switch diagram has the keycap labelled “I.B.M. KEYTOP”, which is shown as truncated in the top view, and cuboid in the side view. The keycap mount is not illustrated, but chances are it will be flat stem mounting.


See the BI-PAC page for more details.


In Electronic Design magazine in 1972 [ED1972-FOK], it was mentioned that CRC also offered reed switches. No details on these were given. Reed switch modules matching the style of the BI-PAC modules can be seen in an unidentified CRC keypad, shown below, with PCB part number 13C0117200-4. The plunger guide shafts of these modules seem to be considerably taller than those of BI-PAC. The production date is not clearly marked, but the PCB is stamped “34 73” which may be the week and year. The photos below were provided by Deepak Kandepet, who made the discovery.

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Top, with keycaps removed to reveal the switches
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Top, with plunger assembly removed to reveal the reed capsules
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Left side, with similar markings to those on Hi-Tek and Stackpole assemblies
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Left side, with plunger assembly removed to reveal the reed capsules
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Reed capsule detail
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Plunger assembly, secured to the PCB with screws
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Plunger assembly base
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Plunger assembly opened
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Plunger assembly components, including annular magnet
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PCB, showing curious arrangement of tracks and connection positions

Identical-looking modules appear in the PLATO IV keyboard, although the details of that keyboard are not confirmed. The rounded corners of the plunger guide shafts and lack of branding match the reed modules above and do not match up with known BI-PAC examples, so reed seems a likely bet here.


C-Scan is a capacitive keyboard design using a buckling rubber sleeve as the return spring.