In these calculators, SET and SELECT keys are used to pick two currencies to be interconverted with the yellow conversion keys at top center. (The €-2002+ has no SELECT key and converts only between euros and a second selected currency.) The euro and 11 participating currencies (all except the Greek drachma) are preprogrammed; the user may add four other currencies--I have programmed all of mine for €/$ conversions (exchange rates between the euro and the dollar, however, are not fixed but float over time).
€-1796: 02000 model; solar-powered with battery backup power
€-2001: Slightly smaller version introduced c. 01999.
€-2000: Another sllightly smaller version. This one is not preprogrammed with exchange rates.
€-2002+: 01999 product that can also be preprogrammed with a tax
rate for easy commercial calculations. Note that the conversion keys only
allow conversion between € and the selected currency.
€-2003: Similar to the €-2002+ but with full interconversion among sixteen currencies.
€-2004: A desktop printing version of the euro-converter.
Further information (in English) on the €-series may be found at the TI United Kingdom site.
The idea of a euro-converting calculator wasn't restricted to TI, of course. First up above is the Troika CAR10, a metal calculator which can be programmed for a single currency conversion. This is a surprisingly heavy calculator which appears here actual size. Next to it is a single-function calculator distributed in Ireland at the time of the euro's introduction which converts between British pounds (the Irish punt was a currency discarded in favor of the euro) and euros at a fixed rate of .79 pounds/€. By restricting its capacity to the two conversions, this calculator gets by with only fourteen keys--the lowest of any calculator in my collection.
If you're interested in currency conversions, try The Universal Currency Converter from xe.com: (This application will send you to xe.com for the answer to your conversion question.)