A few days ago, I started getting "resending previous command (failure response)" errors while uploading commands to the 2414U. Any thoughts on what the trouble might be?
George

Unfortunately, it could be several things: power line noise, malfunctioning 2414U, bad USB cable, USB incompatibility with another USB device or hub, etc.

If it consistently happens and you have the PowerLinc plugged directly into your Mac (and have tried swapping USB cables), then try plugging the PowerLinc itself into a different outlet. Since we are troubleshooting, use an extension cord if you have to. This will change the signal path and may also eliminate excessive power line noise (which is known to cause those errors) since it will be on a different circuit.

Out of curiosity, why would powerline noise affect the Mac-2414 connection? Aren't the USB and PLC decoupled?
George

gmusser wrote:Out of curiosity, why would powerline noise affect the Mac-2414 connection? Aren't the USB and PLC decoupled?

Excessive power line noise causes the 2414U to get confused or bogged down enough that its USB communication starts to fail. I don't know the technical details of why, but I do know that it can happen. Some customers with the exact error you are seeing resolve it by removing or isolating power line noise (often, but not always, by using a FilterLinc on a UPS).