Legacy device registering method, data transferring method and legacy device authenticating method

A legacy device registering method, a data transmitting method thereof and a legacy device authentication method are provided to transmits data according to a data transmission request received from a legacy device. A legacy device authentication method comprises the steps of: receiving the intrinsic information of a legacy device from the legacy device, which requests the registration to a domain by using a virtual client by which the legacy device connects to the domain(S51); inquiring the intrinsic information from a registration possible legacy device list which includes the intrinsic information of a legacy device which can be registered to the domain(S52); requesting the registration of the legacy device from a domain manager which manages the domain if the intrinsic information of the legacy device exists in the registration possible legacy device list(S54); and, otherwise, disapproving the registration to the domain(S55).