Answer:
1: Data line is connected correctly, or whether the two poor contact.
2: Drawing in the software set up inside, check the port selection is correct, language format is wrong (HP-GL or DM-PL language).
3: Plotter Operation window is displayed as "Online" state.
4: If in the "online" interface, and from left to right the first light is red or flashing phenomenon, then turn off the console and then open, (this time the software output file to end task) to reposition the origin, re - Do not locate the car close to the side, so as not to exceed the sensing range.
5: Open the left casing inspection plotter serial inside the host whether there is off-line phenomenon.
6: The final step, consider the data lines for damage.