AOC vs DAC Cables: Which is Right for Your Data Center?

Active Optical Cables (AOC) and Direct Attach Copper (DAC) cables provide integrated, factory-terminated links for high-speed switch and server ports. The right choice depends primarily on distance, cable density, power and budget.

Distance and physical handling

Passive DAC is the most economical option for short in-rack connections, commonly up to 3–5 meters and in some platforms up to 7 meters. AOC uses multimode fiber and reaches tens of meters while remaining thin and lightweight. That makes AOC easier to route between racks and through dense cable managers.

Power, latency and cost

Passive DAC consumes virtually no power and provides extremely low latency. AOC includes electrical-to-optical conversion at both ends, so it uses more power, but the additional latency remains negligible for most data center applications. DAC generally has the lowest acquisition cost; AOC becomes more attractive when distance, weight or electromagnetic interference rules out copper.

Selection checklist

• Use passive DAC for short links within the same rack.
• Use AOC for rack-to-rack runs, high cable density or electrically noisy environments.
• Confirm port speed, form factor, breakout mode and switch coding before ordering.
• Standardize lengths to simplify spares and cable management.

OPTONE supplies 10G through 400G AOC and DAC assemblies with OEM-compatible coding and custom lengths.