Patent ID: 8515349

Claim:
A communication system, comprising: an initiator as a communication device that starts a communication by outputting an electromagnetic wave, and transmits a command via the electromagnetic wave, the command including time slot information; and a target as a communication device that transmits a response to the command by load-modulating the electromagnetic wave, wherein the initiator is configured to perform a first mode communication to acquire real data, the first mode communication including transmitting the command and receiving a response to the command, the response transmitted by the target at a timing of any one of one or more time slots and including the real data, the initiator has first means for causing the command to be transmitted with a first value in the time slot information when the first mode communication is performed and for causing the command to be transmitted with a second value in the time slot information when a second mode communication is performed, and the target has means for recognizing the time slot information included in the command from the initiator, and second means for causing the response including the real data to be transmitted at a timing of a preset time slot, in response to a recognition that the time slot information has the first value, the second means causing a response including an attribute of the target to be transmitted and causing a response including the real data to be transmitted based on the attribute, when the time slot information has the second value.