Photograph of the second page of Esmond Wright's description, dated October 1949, of how the LEO I converter/reconverter should work.  Peter Bird notes in his caption that "The practical difficulties of controlling the gas trigger valves it employed led to its eventual demise". 

The rest of the document is not in the collection.

Research Comments: Esmond Wright was a leading telephone switching engineer at that time, working for Standard Telephones & Cables (STC). Lyons had recently had a new telephone exchange installed by STC and approached them for help in solving the problems of input/output for LEO I, by using magnetic tape. John Pinkerton later pointed out in interview that Lyons' decision that conversion/reconversion needed to take place externally to LEO was probably incorrect and although Wright and his colleagues quite quickly came up with the logic design for both convertor and reconvertor apparatus, using gas trigger tubes which proved highly problematic, the STC equipment never worked properly and was eventually abandoned. A photograph of the 'blueprint' for the system is also in the collection, as is a photograph of a page of Wright's notebook showing a diagram of his initial plan for the decimal/sterling converter. (LM)

Provenance :
Collected by Peter Bird as part of his research for his book LEO - The First Business Computer (1994).