If one end of your serial link is a windows PC, then there's always portmon
- in which case you don't need the splitter cable!

Fairly sure I used custom software with the splitter cable I have (which is
exactly as you describe). I'll have a look and see if I can find it, but
IIRC didn't develop it much as I found portmon did what I needed just as
well or better.

Chris
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