British Calculators

Home > British Calculators > Imperial

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.

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.

Home
Abatron
Addo
Advance Electronics
Ajax
Boots
Busicom / Broughtons
Calate
Commodore
Decimo
Exactus
Geller
Gemini
Gross
Guy's Calculating Machines
Hanimex
House of Fraser
Imperial & Royal
Invicta
Memory Devices
Muldivo
Okhai
Phytron
Plustronics
Prinztronic
Pye
Radofin, Taktile & Triton
Rockwell
Sinclair
Texet

Imperial models

Imperial Office Master
Imperial Office Master Electric
Imperial 860
Royal IC-130
Imperial 80CS
Imperial 81CS
Imperial 81M
Imperial 81SR
Imperial 90S
Imperial 91K
Imperial 91S
Imperial 94F
Imperial 99T
Imperial 1010
Imperial 1020
Imperial 1030
Imperial Companion
Imperial Special
Royal Digital IV
Royal Digital V
Royal Digital 5-M
Royal Digital 5-T
Royal Five GT
Royal Mini Five

Vintage Calculators

© Text & photographs copyright Nigel Tout  2000-2008 except where noted otherwise.