A tremolo device with a movable bridge, an adjustment device, and a support frame is implemented on an acoustic guitar, with features that can also be employed on an electric guitar or other stringed instruments. The system includes a renderer, a proxy, and a workflow manager. The limiter includes a fixing department and a limiting department. A voltage-to-current converter converts the voltage of the loop filter to a current. When the communication information received from the one communication network is relayed to another communication network, information is output to the other communication network by storing information about the failure detected from the communication information received from the one communication network in a header of communication information to be output to the other communication network.