Patent ID: 6973022

Claim:
A digital information receiving system including a first unit for receiving and outputting digital information, and a plurality of second units, which are able to be attached to and detached from the first unit to form a daisy-chain connection via the first unit, for receiving the digital information via the daisy-chain connection, applying processing to the digital information, and sending back processed digital information to the first unit, the system comprising: a plurality of switching means, each provided to a corresponding one of the second units, for switching so as to incorporate the corresponding second unit into the daisy-chain connection or disconnect the corresponding second unit from the daisy-chain connection; an abnormality detecting deciding means for detecting and deciding abnormality of the plurality of second units; and a controlling means for controlling a switching means corresponding to a second unit which is detected and decided to be abnormal so as to disconnect the second unit from the daisy-chain connection, based on a signal from the abnormality detecting deciding means, wherein the abnormality detecting deciding means includes: a test signal multiplexing means for multiplexing the digital information with the test signal before the digital information are passed through the plurality of second units, and a test signal detecting means for detecting the test signal from the digital information which are passed through the plurality of second units via the daisy-chain connection to decide whether or not the detected test signal is normal.