A repeater comprises an EDID memory to store a control data and a memory control unit. The memory control unit is configured to make access to the EDID memory to read the control data therefrom, store the read control data into the EDID memory and, when access is made to the EDID memory by the set-top box, transfer the control data stored in the EDID memory to the set-top box. In this case, the memory control unit outputs an inhibiting signal to a set-top box to inhibit it from making access to the EDID memory until the completion of an operation of storing the control data from the EDID memory in the set-top box into the EDID memory in the repeater.