| 摘要 |
PURPOSE:To ensure the two operations of device selection and control at a control station and to increase the reliability, by making effective the operation of device selction, only if the device selection signal and control signal are not output, and also making effective the control operation only after the selection of device. CONSTITUTION:If all the control and operation switch groups are not selected and operated, the constant mark code conversion propriety signal 33, 3C2 control code signal 34 and selection end signal 21 are all at low level. Accordingly, the device selection lock signal 38 is at high level with an inverting circuit 43, the lock is released and the device selection is enabled, and three control signals 34 are not impossible for control with AND circuits 44-46. When the selection end signal 21 is at high level through the device selection of the control operation switch group, the control signal 34 is passed through while keeping the release of locking to make possible the control. In case of no selection of devices, the selection end signal 21 is at low level at lock state, and neither the device selection nor control signal 34 is transmitted to controlled stations. |
