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Royal Digital IV

Royal Digital IV
Royal Digital IV keyboard
Inside Royal Digital IV

Has no keyboard buttons, but uses an electrical stylus which is touched on the gold-plated pads on the circuit board (above) to enter the numbers.

Royal Digital IV in hand

Royal Digital IV

Display is 8 digits, red LED.


Main integrated circuit - General Instruments GI 251 (date coded 7203).

7.2 v (6 x AA rechargeable cells).

81 mm x 165 mm x 39 mm (3.2" x 6.5" x 1.6").

Introduced January 1972.

Made in U.S.A.

From the magazine "Electronics", Jan. 3rd, 1972 -
"Royal Consumer Products division, Hartford, Conn., a part of Litton Industries. With its Digital III and IV, made by the Monroe division of Litton, Royal is in a position to market these units to consumer outlets, from mass merchandisers to the corner stationery shop. With quantity discounts and prompt payment, dealers get these machines for under $90. Suggested retail prices are $139 and $149."

Price in UK, June 1972, £52-50.


At this time calculator keyboards were complicated and expensive components. To cut this cost this calculator shows gold-plated pads on the circuit board through the front of the calculator. Touching a pad with the electrically connected stylus has the same effect as pressing a key on a standard calculator.

Only this model and the Royal Digitial III are known to have this stylus feature.

Vintage Calculators

© Text & photographs copyright Nigel Tout   2000-2019  except where noted otherwise.