A PAN, or Personal Associative Network, was an ID system in use on Earth in 2040.
It functioned as a driving licence, passport, bank card, medical sensor, communications device and entertainment system. A PAN could be rolled up like a piece of cloth. Some people attached earpieces or microphones to their PAN. (PROSE: /Carpenter/Butterfly/Baronet [+]Gareth Wigmore, Short Trips: 2040 (Short Trips short stories, 2004).)