During Cartes 2009, 2000 participants , including congressists and journalists , will receive a USB key with one giga bytes of memory , compatible with Calypso.  Thus this key will alow them to take the public transport (areas 1 to 4) during the duration of the conference , from 17 th of november until 19 th of november, without obligation to stand in line for buying ticket. It is also an ecologic initiative as all the presentations made during the conference will be recorded in the key without wasting paper.