摘要 |
<p>An electronic user device (EUD) (1) with a source (3) of electric power charged up by a check-in device (CID) (8) has first (6a) and second (6b) communications interfaces available, the first of which is attached to a communications link (7) with the CID so as to start detection/recording. The CID activates the EUD and can communicate with the EUD by exchanging data.</p> |