Synergistics was founded on the 13th of May 1960 in Massachusetts as Kilbanon Corporation. The business was described in the article Who’s Who in electronics, Computer Design, September 15 1969 as “only a corporate shell” until William M Tetrick became the company president in March 1968. By this point, the company had been renamed as Synergistics, Inc., as of the 10th of October 1967.
The keyboard line of business was gained from the acquisition of Peripheral Equipment Corporation (stated in the aforementioned Computer Design article to be “Peripheral Data Systems”). Peripheral Equipment Corp. was founded on the 24th of October 1966 in Worcester, Massachusetts, and on the 10th of June 1968 it was merged into Synergistics. Their product line at the time was described as “computer-compatible credit cards and card readers, and a low-cost line of self-encoding keyboards for data entry.” (A separate and seemingly unrelated Peripheral Equipment Corporation existed in California who filed patents between 1971 and 1974.)
Peripheral Equipment Corp. was not their sole acquisition at the time. Synergistics also gained Ikon, Inc. (or “Ikon Data Systems”) in December 1968, a computer communications manufacturer, and in August 1968 they obtained laser data recording technology from Sylvania.
A separate firm Synergistics Aquisition Corp. was formed on the 18th of July 2002, into which Synergistics was merged on the 2nd of October 2002. This new company changed its name to Synergistics, Inc. on the 11th of March 2003. Finally, Synergistics acquired the Millennium Group, Inc. on the 1st of January 2014, also of Natick, Massachusetts. The Millennium Group name was adopted for the business upon merging.
Synergistics manufactured a line of mechanical encoding keyboards, whose operation is covered in US patent 3499515 “Modular electrical keyboard” filed in December 1967. These keyboards contained no logic circuitry: the external connector simply exposed the encoded bits from the switches. Each row of keys was provided with a common output bus for the encoded output; a separate bus for external connector joined these together. Each key station contained a number of flat-head pins driven into the bus lines: the pointed tail pierced the bus line to form a permanent connection, and the flat head provided a stationary contact. Attached to each keycap is a piece of spring metal in the form of multiple movable switch contacts extending from a common centre, which connects together all the pins when a key is operated. The encoding of each switch is set using an insulating mat, with break-off tabs for each output bit. Intact tabs prevent the corresponding contact pair from conducting; removing a tab enables a specific output bit.
Despite being a common bus design, there is no indication that any means was employed to prevent collisions from overlapping keystrokes. A suitable method for such a design is an electrical monitor line connected to each switch by a resistor, allowing the number of concurrently-actuated keys to be detected using a change in resistance, but no mention of this technique or any alternative approach is reported in the patent, the advertisements or the magazine write-up.
The switch is described briefly within Users’ choice is name of keyboard game, in Electronics magazine in November 1969. The rated lifetime is given as over 10 million cycles. Confusingly, the summary table lists the logic as “diodes in key”, which is not only absent from the patent, but also meaningless because the design has no need of any such diodes. Mechanical Enterprises Mercutronic, covered within the same article, does have diodes within each key, but this is mandatory for their design as it only has one set of contacts per switch that are connected in turn to all the bus lines; there, the diodes define the encoding and prevent wrong-direction current flow. The Synergistics design, as with Micro Switch KB encoding switches, uses a separate contact pair per output bit, removing the need for separate diodes.
The following diagram shows selected components from the switch, based solely on diagrams from the US patent. The specifics of full-scale production implementations are not known, as no Synergistics keyboards are presently known to have been encountered. The diagram omits such components as the flat metal plunger, the keycap, the return spring and the electrical buses. The diagram primarily demonstrates the switch contact assembly and how the output from each switch is selected.
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