Application protocol data units are conveyed in a universal serial bus so that a portable electronic object such as a smart card can be recognized by a terminal, such as a micro-computer, as being a peripheral. The header and the data field, when such a data field exists, of each command are encapsulated in data fields of data packets of respective downlink transactions. The data field, when such a data field exists, and the trailer of each response are encapsulated in the data packet data field of at least one uplink transaction. By means of this bus link, the data rate between the terminal and the electronic object is higher, and a plurality of portable electronic objects can be connected to the terminal.