C. P. Clare & Company
C. P. Clare & Company, Pendar, Clare-Pendar, Clare, General Instrument and the separate Pendar Électronique in France have together a complex and still poorly-understood history. See history for the most recent reconstruction of this history. For products specific to General Instrument (in particular semiconductors) see the separate General Instrument section. This section only covers product ranges under official Clare or General Instrument ownership; see the Pendar section for the unrelated activities of the separate Pendar Électronique that followed a buyout of European production from General Instrument.
Following C. P. Clare’s acquisition of Pendar in 1966, keyboards and keyswitches were produced under the Clare-Pendar name; this can be seen in magazine advertisements from 1970–1976. Keyboard advertisements in 1978 (of which there were numerous) used the C. P. Clare name instead, and in the 1980s the keyboards were sold as General Instrument products.
Clare-Pendar were one of the companies to adopt matrix scanning around 1970: a Clare-Pendar advertisement in Electronics magazine in November 1970 describes their LSI/MOS–encoded matrix scan keyboards. These keyboards were scanned at 50 kHz, taking 20 microseconds to scan each key. The encoder supported either three modes or four levels (the article claims both) and 9-bit output codes for up to 88 keys in 2000 bits of ROM; something seems wrong, as 88-key 9-bit tri-mode would require 2376 bits of ROM, and quad-mode would require 3168 bits. The scanning process was advertised as having much less power consumption than Hall effect, at 200 mW vs 5 W for Hall effect. The price per keyboard was listed as $250 in small quantities, with production quantities expected to bring the price below $100 per unit. These keyboards used reed switches.
Initially a reed keyboard manufacturer, Clare-Pendar also turned their attention to mechanical switch keyboards. No literature is known for their Series S840 keyboard switches, but keyboards using them (such as the Bendix keyboard made for NASA, and some Texas Instruments Silent 700 keyboards) can be found as far back as 1973.
Under the C. P. Clare and General Instrument names, they also produced foam pad capacitive keyboards.
In 1978, they advertised microprocessor-based “intelligent” keyboards, in both reed and capacitive forms.
The North American and European products had some crossover in the form of the low-profile reed switches, but were otherwise separate. US-made switches were sometimes branded C.P. Clare, Clare-Pendar or GI, but S840 series in particular seems to have always been marked only as “ASM MEXICO” indicating assembly in Mexico.
|S700||“ASM MEXICO”||Low-profile foam and foil with hysteresis; the sliders are marked “ASM MEXICO” while the PCB bears the series name and “General Instrument Computer Products Division”|
|S820||Clare-Pendar||Reed (tall); a later design has been found marked both “CLARE-PENDAR” and “ASM MEXICO”|
|S830||Clare-Pendar, G.I.||Reed (tall)|
|S840||“ASM MEXICO”||Metal contact|
|S880||None; “ASM MEXICO”||Reed (short)|
|S890||CP Clare, “ASM MEXICO”||Foam and foil|
|S950||General Instrument||These are a derivative of Alps KCC/SKCC Series, and may have been manufactured by Alps Electric on behalf of General Instrument (otherwise, Alps must have sold the plans to the tooling).|
The modifications chart also mentions S860 series but Electro-Mech have no documentation on this.
- Clare-Pendar K353 53-key teletypewriter keyboard (on sale for the thrifty price of only $3,500); the switches are not specified in the parts of the datasheet visible, but may be S820 (the depicted item is ca. 1973); there is also a model K453 according to the listing
Patents relevant to Clare/Pendar computer keyboards and switches.
|Clare Pendar Co||US 3771636 A||Space bar assembly||1971-04-02||1973-11-13||This is the characteristic Clare-Pendar space bar assembly with the interlocking bars|
|General Instrument Corporation||EP 0072784 A2||Keyswitch design||1982-08-10||1983-02-23||A design for a single-sided foam and foil PCB where the capacitor pads are through-hole soldered!|
|General Instrument Corporation||US 4450332 A||Keyswitch design||1982-08-25||1984-05-22||This appears to be for the foam and foil switch series mentioned earlier|
|General Instrument Corporation||US 4454562 A||Keyswitch with telescoping plunger||1982-09-15||1984-06-12|
|General Instrument Corporation||US 4453198 A||Linear feel keyswitch with hysteresis||1982-09-15||1984-06-05||That is a strange definition of “linear”|
|General Instrument Corporation||US 4433225 A||Keytop levelling mechanism||1983-02-22||1984-02-21||This may be the origin of scissor switches|
Some North American–made products have “97564” moulded into them or stamped on them, which at least one supplier has since mistaken for a manufacturer part number. This is in fact the CAGE (Commercial and Government Entity) code. Depending where you look, this number has been applied to:
- Clare-Pendar (moulded into S830 switches which are Clare-Pendar branded)
- General Instrument Corp., Computer Products Division (one of 16 separately-numbered General Instrument divisions listed on bjg-design.com)
- Pollak Corp (according to most sites); also listed in full as POLLAK CORP (TRANSPORTATION ELECTRONICS DIV)
- Electro-mech Components, Inc. (per AeroBase Group)
- Clare-Pendar MOS keyboards advertisement, Electronic Design, Vol. 18 No. 15, July 19 1970, page 12
- Clare-Pendar LSI-MOS keyboard announcement, Electronics, Vol. 43 No. 23, November 9 1970
- Clare-Pendar LSI-MOS keyboard advertisement, The Electronic Engineer, Vol. 30 No. 9, September 1971
- C. P. Clare reed keyboard advertisement, Computer Design, April 1978, page 43
- C. P. Clare microprocessor reed keyboard advertisement, Computer Design, May 1978
- C. P. Clare Thinking Cap keyboard advertisement, Computer Design, May 1978, page 219
- C. P. Clare intelligent capacitive keyboard advertisement, Electronic Design, Vol. 26 No. 12, June 7 1978
- C. P. Clare R53-LTT keyboard advertisement, Computer Design, June 1978
- C. P. Clare intelligent capacitive keyboard advertisement, Computer Design, July 1978, page 171