The CD400 was build for Olympia by a Japanese company. A rather unique design aspect is the usage of an acoustic delay-line memory. This type of memory was shortly in use for this kind of purpose. The keys activate reed-switches. This was a common approach in the early days of electronic calculators.
For its design Olympia received the IF Design Award 1971
Use the “+=” and “-=” key. Using the circled version stores the result in memory.
Enter 1st number, push the “X”-key, enter the 2nd number, push the “+=” key.
To add the result to memory use the circled “+=” key
Enter 1st number, push the “:”-key, enter the 2nd number, push the “-=” key.
To add the result to memory use the circled “-=” key
Function of some keys, switches etc.
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Probably mid 1970 (regarding prints on IC’s)
Addition, Subtraction, Multiplication, Division
DM. 2150 in 1971/1972 (Source: Büromaschinen Lexikon)
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