I've always wondered whether network interfaces that have these flashing lights flash as a gimmick or do they actually indicate the flow of traffic? Perhaps one flash per packet in or out? I wish I could remember what my call up modem looked like to make a historical comparison too.
TL-SG105E
In 10MB ethernet days, they might have been directly driven by the signal on the wire. After that, they’re pretty much just “a flashing mechanism turned on when activity is present”
I was leaning towards this conclusion too. I wonder where my modems went... Already looked in the cellar.