Provided is a system for communication. The system includes: a basic function module; at least one extended function module; a first near-field communication transceiving unit and a first near-field communication antenna unit, located on the basic function module; and at least one second near-field communication transceiving unit and at least one second near-field communication antenna unit, located on each of the at least one extended function module. The first near-field communication antenna unit and the at least one second near-field communication antenna unit respectively comprise a first loop antenna and a second loop antenna which are printed on a printed circuit board.