an expandable exchange apparatus and a backup system thereof are disclosed . the expandable exchange apparatus is applicable to a plurality of terminal devices in a local area network . the expandable exchange apparatus includes a signal exchange unit having a network connection port and a plurality of terminal connection ports connectable to the terminal devices , a connection unit connecting the lan to an external network architecture , and a first exchanger connected to the network connection port and the connection unit , the first exchanger selectively connectable to a terminal device that is connected to none of the network connection port and terminal connection ports of the signal exchange unit , wherein , detects whether the network connection port is connected with the terminal device or not , and based on a detected result , correspondingly switches a data transmission path of the network connection port either to the lan or to the network architecture .