What's Calypso ?

Calypso is the electronic ticketing standard which defines the secured dialogue between cards and terminal

It was developed by a group of European partners from the cities of Brussels in Belgium, Lisbon in Portugal, Konstanz in Germany, Paris in France and Venice in Italy

The 10 years development program, succeeded in creating the smartcard contactless technology adapted to the public transportation uses.
Some functional choices have been taken into account to answer the transit operators' needs:

The technology was made accessible to all manufacturers on a fair and non-discriminatory basis, to ensure: