DAC and AOC cables both provide fixed, plug-and-play connections between two ports, but they solve different problems. A DAC (direct attach copper) cable carries electrical signals over twinax copper and offers advantages in cost, power consumption, and latency for short in-rack connections. An AOC (active optical cable) converts electrical signals into optical signals inside the cable assemblies and is better suited for distances of 7 to 100 m, EMI-sensitive environments, and applications requiring thinner, lighter cabling.<\/p>\n\n\n\n
The most expensive cabling mistake is rarely the cable itself. It is the rework that follows when a 3 m passive DAC fails to establish a reliable link at 800G.<\/p>\n\n\n\n
The old rule\u2014copper for short links and fiber for long ones\u2014was adequate at 10G. It is no longer sufficient at 100G, 400G, or 800G, where passive copper reach decreases as signaling rates increase and active electrical cables (AECs) have become a practical third option.<\/p>\n\n\n\n