According to one embodiment, first monitor controller of electronic circuit board recognizes free slot into which the electronic circuit board has been hot-inserted, notifies host control device of start together with slot information causes first parameter setting module to change reception parameter of first T/R circuit module. The host control device instructs switch processing board to change transmission parameter, in response to slot information and start notification. Second monitor controller of the switch processing board causes second parameter setting module to change transmission parameter of second T/R circuit module, in accordance with an instruction from the host control device.