Now, how this signal is generated. In the traditional automobile environment, the operator or the authorized person on the defect producing station pulls the hanging rope (above the station). This rope is connected to all the lines. And pulling the rope from any point leads to the shut down of all the connected lines.
The method of generating signal was modified to electronic means, when the rope was replaced by a button available on all the stations. This button, when pressed via common electrical supply shuts down all the connecting production lines. And immediately, the Andon board, with all the stations labeled on it, starts indicating that problem is occurring on a particular station. And recently, with the improvement of Internet and Information Technology this is done by use of sophisticated electronics and software.
This system was enhanced and implemented to an extent, that even the supplier and customer plants were sometimes stopped by the signal.