A communication system may be provided with a first communication device and a second communication device. The first communication device may send the identification information stored in a first storage device to the second communication device. The first communication device may output status information included in combination information sent from the first communication device, and update the stored contents of the first storage device such that identification information included in the combination information is stored in the first storage device. The second communication device may obtain status information concerning a status of the second communication device, and update the stored contents of a second storage device such that the latest combination data including the latest status information and new identification information is stored in the second storage device. The second communication device may send the latest combination information to the first communication device in a case where the received identification information is not identical to the identification information included in the latest combination information, and prohibit the sending of combination information to the first communication device in a case where the received identification information is identical to the identification information included in the latest combination information.