Unfortunately I had to find why I just get confused characters on the terminal only once. Solution: The black ground lead, although introduced in the plug but not pressed properly. This of course this had no contact and gives a data transfer in which the reliability is determined by chance. From a product in this price range I would have expected more care in the production / quality control. After soldering all the same 4 Plug the function is easy. Troubleshooting is easily feasible with a simple multimeter to continuity test.