To prevent interference between plural adjacent readers or/and writers and the malfunction of plural adjacent non-contact type IC cards in a non- contact type IC card system.
Reader or/and writer antennas 101a and 101b are driven so that their phases can have a relatively inverted relation between reader or/and writer devices which adjacently arrange radiated electromagnetic fields of the antennas 101a and 101b which are provided in plural reader or/and writer devices 1a and 1b which are adjacently arranged.
|JP2005135136||MOBILE COMMUNICATION DEVICE|
|JP2005347870||IC TAG COMMUNICATION RELAYING APPARATUS, AND IC TAG COMMUNICATION RELAYING METHOD|
|WO/2001/052181||WATERMARK EMBEDDER AND READER|