1970 · Battery Printing Calculator · Work 932 of 1,871
A commuter train in Tokyo on an autumn evening, two hands in dark suit sleeves holding a printing calculator on a black leather briefcase across the knees, an upright device twenty centimetres tall with a grey-white frame, a dark brown-black key field of white keys and pale blue keys, all plain smooth and unmarked, above them a black band with a narrow window and a small red key, at the top a roll of paper under a clear plastic flap, a short curl of blank white paper rising from it, through the train window city lights soft and blurred, warm carriage light.
What it was used for
Canon put the Pocketronic, a small printing calculator based on Texas Instruments' Cal-Tech, on sale in Japan in October 1970 and in the United States in January 1971, at a list price of 359 dollars. It calculated to 12 digits, 8 before and 4 after the point, using 3 MOS-LSI circuits from Texas Instruments (TMC1730, TMC1731, TMC1732) on 1 watt at 16 volts. The Pocketronic had no display at all: every entry and every result appeared on a paper strip written by a serial thermal printer with a 5 × 7 dot matrix. It weighed 1.8 pounds and measured 4 × 8 3/16 × 1 15/16 inches.
What was new
What marked it was the chip set: 3 MOS devices from TI did the work for which the 1967 Cal-Tech prototype had needed bipolar gate arrays and shift registers; bipolar logic was too expensive at this scale. Who was on sale first depends on what is counted: the Pocketronic was available in Japan from autumn 1970, the Sharp EL-8 from January 1971 and the Busicom LE-120A from early 1971, but both with a display instead of a paper strip.
What the sources leave open: The Old Calculator Web Museum gives 359 dollars on its specification sheet and 400 dollars on its Cal-Tech page as the US list price; the figure used here is the one from the specification sheet. Neither page gives a battery run time.
Connections
Every connection names its kind. “Forerunner” on its own would be a claim.