Old thread, but I just went through this nightmare. Machine sat in storage for 10 years (Heller reflow oven). Modicon TSX Nano TSX07 2428 V3.0 was flashing Error LED. Downloaded PL707 V4, made 2 floppies, and installed on system's IBM PC running DOS 6.22. Bought TSXPCU1030 because that was the "DOS" version. No comms. The solution is to build an adapter cable, described here in a document from Schneider. In case the thread dies, it's 2-2, 3-3, and 5-5. Add a jumper on PC side, 7-8. Add a jumper on TSXPCU1030 side, 3-7. From the document, I assume the TSXPCX1031 cable would have worked without this adapter. Next issue was the fault. Program is stored in EEPROM, but executes in battery-backed RAM. The cure was to use one of the software functions to copy program from EEPROM to RAM. Next challenge is to find out how to replace battery. Option is to port software over to a newer product. Rotary switch is address. Zero for PLC, one for first expansion unit, etc.