A Tour of Company Sites

Plus & Sumlock Mechanical Calculators
PLUS 509/D

PLUS 509

Plus model 509/D

Simple "Comptometer" type adder.

This is a direct action keyboard calculator of the "comptometer" type. It has an abbreviated keyboard (keys up to 5) and is designed for decimal calculations.

235 x 182 x 120 mm (9.25" x 7.2" x 4.75").

The machine illustrated has serial number 509/D/892604.

Made in or after 1966, when Sumlock Anita Electronics was formed to manufacture the electronic and mechancal calculators.

Label

The label showing that this is a later machine, made when the manufacturing company was known as Sumlock Anita Electronics Ltd.

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Introduction
Origins of Bell Punch Co.
Mechanical Calculator Days
National Calculating Service
Development of Anita 1
Development of Anita 2
Anita is Launched
At work with Anita
All Change at Bell Punch
Anita Developed Further
Anita at its Zenith
The Rockwell Connection
Demise of Anita & Bell Punch
Mechanical Calculators
Early Anita Desktop Calculators
Transistors & Integrated Circuits
Anita LSI Desk Calculators
Anita Hand-held Calculators
Rockwell-Anita Calculators
Calculators made by others
Advertisements & Brochures
Operating Manuals & Materials
Company Information
A Tour of Company Sites
Summary
The Technology Explained
Operating a Comptometer
Old Sterling Currency, £sd
Links
Update Information
Getting in touch

Plus & Sumlock Mechanical Calculators

Plus Adder S
Plus Adder SJ
Plus Adder ST
London Computator 509/S
London Computator 912/S
Plus 506/D
Plus 506/F
Plus 506/T
Plus 509/D
Plus 509/F
Plus 509/S
PLUS 509/SP Weight Calculator
PLUS 509/T Time Calculator
PLUS 509/Y Weight Calculator
Plus 512/S
Sumlock 912/F
Sumlock 912/S
Sumlock 912/Y Weight Calculator
Sumlock 913/S with Certopost
Sumlomatic
Sumlock Comptometer 993m
Sumlock Comptometer 993s

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Text & photographs copyright © 2002 - 2009 Nigel Tout, except where noted otherwise.