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
Display is 8 digits, red LED.
4-function.
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.
Imperial models
Vintage Calculators
© Text & photographs copyright Nigel Tout 2000-2019 except where noted otherwise.