A printer that communicates with a point-of-sale device, the printer comprising: a wireless communication unit configured to perform wireless communication at a predetermined communication frequency; a memory that stores a communication address by which the POS device can wirelessly communicate with the printer; and a processor configured to generate a communication setting pattern by encoding the communication address and the predetermined communication frequency, and wherein the processor is configured to - receive the confirmation response transmitted by the wireless communication unit from the POS device through the wireless communication, - determine whether or not the received confirmation response contains the communication address that coincides with the communication address stored in the memory, and - in a case where the received confirmation response contains the communication address that coincides with the communication address stored in the memory, transmit the confirmation response to the POS device by using the wireless communication unit, characterized in that: in a case where a communication path is established between the printer and the POS device, in a case where the printer receives a change request of a communication channel including information indicating a communication channel which is newly used for the wireless communication with the printer to the printer, the printer is configured to: - recognize the communication channel which is newly used for the wireless communication with the POS device from the change request of the communication channel, - transmit a response to the change request of the communication channel to the POS device, and - rewrite the communication channel stored in the memory of the printer to the communication channel which is newly used. a wireless communication unit configured to perform wireless communication at a predetermined communication frequency; a memory that stores a communication address by which the POS device can wirelessly communicate with the printer; and a processor configured to generate a communication setting pattern by encoding the communication address and the predetermined communication frequency, and wherein the processor is configured to - receive the confirmation response transmitted by the wireless communication unit from the POS device through the wireless communication, - determine whether or not the received confirmation response contains the communication address that coincides with the communication address stored in the memory, and - in a case where the received confirmation response contains the communication address that coincides with the communication address stored in the memory, transmit the confirmation response to the POS device by using the wireless communication unit, - receive the confirmation response transmitted by the wireless communication unit from the POS device through the wireless communication, - determine whether or not the received confirmation response contains the communication address that coincides with the communication address stored in the memory, and - in a case where the received confirmation response contains the communication address that coincides with the communication address stored in the memory, transmit the confirmation response to the POS device by using the wireless communication unit, - recognize the communication channel which is newly used for the wireless communication with the POS device from the change request of the communication channel, - transmit a response to the change request of the communication channel to the POS device, and - rewrite the communication channel stored in the memory of the printer to the communication channel which is newly used.