Device having a digital interface and a network system using such a device and a copy protection method

摘要

A copy flag detecting circuit in a device detects the copy generation management information. This copy generation management information is inserted in the CIP header of the IEEE 1394 packet for transmission. The copy flag detector of the 1394 interface in the device detects the copy generation management information in the CIP header. According to the detection result, the copy generation managing circuit records new copy generation management information and the recording controlling circuit permits or prohibits recording. Thus, there is no need for a decoding circuit at a receiving device.