| 摘要 |
PURPOSE:To perform control of a printer at the same time only with a video signal line, by superimposing a different signal on a video signal or eliminating the video signal, of the printer, and detecting the elimination or superimposition at the printer, and starting the control of the printer. CONSTITUTION:When a switch 1 is changed over to ground side, a video signal is lost. On the other hand, a printer is provided with a video signal detector 3 at the printer to detect the missing of the video signal. The operation of the printer is started based on this detection signal. Further, a video device is provided with an oscillator 4 separately, a switch 5 is changed over to this oscillator 4 to superimpose a different signal on the video signal, and this different signal is detected at a detector 6 at the printer to start the control of the printer. |
