JPH0630047B

PURPOSE:To facilitate the extension of video terminals by providing a video signal switching circuit for every video terminal and providing first and second changeover switches interlocking by an output from a reception circuit corresponding to a selection request signal. CONSTITUTION:The video signal switching control circuits 33, 34 are disposed for every respective video terminals VT1, VT2. When the selection request signal is inputted to transmission and reception circuits 31, 32 from a video signal processor 21, the first change-over switch (input side relay switch) 27 is switched so as to supply a video signal from a video terminal controller 22 to the second change-over switch (output side relay switch) 26 side. Simultaneously, the second change-over switch 26 is switched so as to supply the video signal to the processor 21 side. When the selection request signal is cancelled, the switch 27 is switched so as to feed the video signal to a video monitor part 23 side and the switch 26 is switched so as to feed an output from the second switch (output side relay switch) 28 to the processor 21 side.