HI, I'm having some trouble with a project I'm doing. It consists in reading a BarCode from a tool box and depending of it deciding which output to turn on, so we can show the worker the correct position in a rack. As you may know the program is very easy, what I can't do is see what the Barcode Scanner reads in the PLC, so I have nothing to compare to! I have a S7-300 CPU 313C 2-PtP, with RS422 and RS485 Communication Protocols. Also my Barcode Scanner is a Symbol MS4404, which has only RS-232 Communication, so I also have a RS-232/RS485 or 422 converter. This converter has 2 LEDs, one that indicates that it is Receiving data, and another one that indicates it is Transmiting data. This two LEDs flash continuously when I put my PLC in RUN mode, with a SENDING-RECEIVING program that I downloaded from SIEMENS Web page. But still can't see what is the PLC Receiving, or if it is Receiving somthing at all! I'm attaching a copy of the program. Error_pr2.zip Hope you can help me...