Datanetics DC900-0067-1

DC900-0067-1 is a batch-fabricated array (membrane) keyboard from Datanetics. This model, made in November 1971, uses a MOS (LSI) single-chip encoder, compared to the TTL encoder in Datanetics 01-02-638 from December 1970. Although the part number is now in the DC900 range, the PCB has “CKT BD” number “01 02 1554” and is also marked “SW ASSY 01 02 1560”.

The switch plungers bear a strong resemblance to those in US patent 3773997A “Key assembly diaphragm switch actuator with overtravel and feel mechanisms, yet this is a linear keyboard (the patent is for a switch with tactile feedback and hysteresis). The 1970s examples do not use the same plungers. Two switch mounts were severed during attempts to remove keycaps, although one keycap had already almost detached. Care should be taken when attempting to remove keycaps from these switches.

The alphanumeric keycaps and some of the special keycaps are double-shot injection moulded, while the remainder of the special keys are engraved and infilled.

The markings on the encoder as follows:

UA3533D
6019
7133

“7133” will be the date of manufacture (week 33, 1971). The other markings do not immediately indicate the manufacturer of the chip.

The example below, serial number 001, belongs to John Styll, son of the late Datanetics president Marshall Styll, and he kindly provided the following photographs of it: