AEC · Active Electrical Cable
Copper cable with a redriver or retimer in the connector, buying a few metres of reach past passive DAC at a power and reliability cost; it sets the distance where optics become unavoidable.
Current numbers
passive ~1-2 mcopper reach at 800G/1.6T: passive DAC ~1-2 m, active (AEC) ~3-7 m; optics beyond — the domain-size wall
~1–7 mcopper reach budget at 800G: passive DAC ~1–2 m, active AEC ~3–7 m, optics beyond — caps physical topology
~1-2 mpassive DAC reach at 224G; active copper (AEC) ~3-7 m; optics beyond — reach halves as lane rate doubles