I had my TX/RX running, getting it's signal from a LOR iDMX. I was screwing around with a sequence for a while, not paying attention to the Express that was hooked up with an EX/RX. It must have been 20 to 30 minutes of inactivity (not playing a sequence), and I noticed the green Data Link LED on the LE was off, I did the same thing (unplug, replug) to the LE and the Data Link light came back on, and everything worked great. I figured it was the inactivity of the iDMX.