About this Site

This site grew out of a realisation that there was a growing calculator collecting community on the internet, and that some interest was apparent for calculators made by the innovative, and British, Sumlock Anita company that was an offshoot of Bell Punch that had made comptometers before moving into the electronic calculator field. Indeed it had pioneered this field.

My own family connections with this company (see here) sparked an interest in collecting calculators made specifically at the factory in Portsmouth that was set up in the 60's for making the Anita calculators.

Having collected a few handheld calculators (and a Bell Punch abbreviated comptometer) I moved into writing simulators so that others might have an experience of how these calculators operated, and their look and feel (as much as is possible in a simulator). And a desire to simply document what I had learnt.

So this site was born to bring together all of the elements I had collected so far. Pictures of the calculators, access to the simulators and other articles I'd written from my own experiences (the little that I know). I hope people enjoy the site and learn a little of the calculators. Feedback on the site is always welcome. Please use the contact details at the bottom of the left hand frame.

Brief Company History

Sumlock Anita Electronics Ltd. was an innovative British company, set up as an offshoot of the Bell Punch company that originally made ticketing machines and "comptometers" under the Sumlock name, such as the Plus model 509/S. They then moved into electronics and made the world's first electronic desktop calculator, the Anita Mk VII. Sumlock, based in Uxbridge with a factory in Portsmouth, went on to produce successful calculators in the Anita range like the desktop Anita 1000 LSI, and hand-held calculators in the 800 range, like the Anita 811. The company was bought by Rockwell (that had supplied the LSI chips for the later calculators) in 1973, and for a while made calculators under the Rockwell name, like the 30R, or branded for other companies, like the House of Fraser 18F, until being shutdown and manufacture moved elsewhere. For more details about Anita calculators visit Voidware's website here. For a fascinating history of Bell Punch and the Anita calculators visit Nigel Tout's excellent website by clicking here. Further useful links may be found at the links page.

The simulators

The Javascript simulators use images from various sources. Most of the images come from calculators in my own personal collection. Others come from images used with permission from other collectors, and some are composite images, made from a base calculator image with images added from other calculators or manipulated within a graphics package. It has been my intent to present the simulators with the images as near perfect as is possible, to give a flavour of what these devices were like when new. To this end most of the images have been manipulated to remove blemishes, rogue sticky labels, cracks and general marks from wear, as much as is possible. The images on the pages describing the calculators in my own collection use exactly the same source images as on the simulator main page, and are thus equally deficient of blemishes. I make no apologies for this---the effort, as well as increased server disk space requirement, is simply not worth it as far as I am concerned. I mean no deception in this regarding the quality of the devices in my collection, but as I am not selling the items I feel none is implied. This notice serves to inform the reader that the images have limitations with respect to the accuracy of the actual state of my calculators.


Grateful acknowledgement goes to Hugh Steers for permission to use the Anita 841 image (used in the 8041), and also many thanks to Tony Thimet for allowing the use of his Triumph 81 image. Thanks to Gerhard Wenzel for the use of the Radio Shack EC220 image, and many thanks as well to Nigel Tout for publishing the Anita 831 and 841 manuals on his website, without which those simulators could not have been completed. All images used with permission remain copyright to their respective owners.


David Southwell. Chief Test Engineer, Sumlock Anita Electronics, Portsmouth;
and Olwen Southwell (nee Hunter), a "test girl".

This site is dedicated to all the men and women who made Sumlock Anita Electronics the ground breaking company it was, and to my father David Southwell (1931-1981) and mother Olwen Southwell (1929-2006) who were part of that glorious history.

Simon Southwell

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Last updated 21st December 2004.

© 2003-2004 Simon Southwell. All rights reserved.