Patent ID: 7027042

Claim:
A display apparatus communicating with a video card provided in a computer main body, comprising: a first video signal processing part which processes a video signal output from the video card provided in the computer main body and displays a picture thereof; a picture data storing part; and an error detecting part which captures the video signal at predetermined intervals, stores picture data of the video signal in the picture data storing part, compares the stored picture data to each other after elapse of a set time, outputs a first error signal to the computer main body in response to the stored picture data being equal to each other, captures and stores the picture data of the video signal at the predetermined intervals after the outputting of the first error signal, compares the picture data stored before the outputting of the first error signal with the picture data stored after the outputting of the first error signal, and outputs a second error signal to the computer main body in response to the picture data stored before the outputting of the first error signal being equal to the picture data stored after the outputting of the first error signal.