Active electrical cable (AEC)
Beginner
A copper cable with small booster chips in its plugs so it can reach farther.
Novice
A copper cable with a retimer chip in each plug. The retimers clean up the signal, which lets copper reach a few meters further than a plain cable, at the cost of some power.
Expert
Twinax with a retimer in each connector shell (a non-retimed active copper cable uses a linear redriver instead). Reach of several meters, beyond passive copper; the retimers add several watts per end.