A printer that communicates with a point-of-sale (POS) 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. <EOS>