Hello, I am new to PLCs (but not embedded development) and I need some things cleared up about the project that I am working on. The device that I am working with is a FX1N with the 232-BD attachment. I am trying a little reverse engineering to better understand the software that I am trying to fix. The PC application periodically sends a string of data to the FX1N, I am assuming that the data gets written directly to the FX1N's memory somehow because the ladder code does not make any mention of the RS232. Anyway, I read the spec for Mitsubishi about communications, but the data that I am seeing sent out does not seem to match up with the spec. Can someone help me decode what I am seeing? There are 2 functions that get called all the time, write and read. the write data function sends out a 0x02 (this part matches to the start of text character) and then sends out this, E1040E61000000000000000000000000000000100 followed by a 0x03 ( end of text) The read function does something similar. Where is this data being stored to on the FX1n? Thanks, Ben