Patent ID: 7712663

Claim:
A communication board comprising: a plurality of antennas configured to transmit and receive a signal by electromagnetic induction, where each of the plurality of antennas is provided on a substrate, as a coil-shaped pattern; a semiconductor chip mounted on the substrate, the semiconductor chip including a plurality of transmission and reception circuits, each of the transmission circuits transmit a signal to one of the plurality of antennas and each of the reception circuits receive a signal received from the one of the plurality of antennas, a transmission circuit and a reception circuit are asynchronous circuits, and the remaining transmission circuits and reception circuits are synchronous circuits; and an input-and-output end that is connected to the semiconductor chip via a wiring layer provided on the substrate and an electronic circuit of the electronic device, wherein the communication board communicates with another communication board via at least one of the antennas by electromagnetic induction.