2025-03-20 0

Difference Between AOC and DAC Cables

Difference Between AOC and DAC Cables

Definition

  • AOC (Active Optical Cable): Uses optical fiber as the transmission medium with built-in optical-electrical conversion modules for high-speed data transfer.
  • DAC (Direct Attach Cable): Uses copper wire as the transmission medium, commonly used for short-distance high-speed data transmission.

 

Comparison AOC (Active Optical Cable) DAC (Direct Attach Cable)
Transmission Medium Optical fiber Copper wire
Transmission Distance 3m~100m 1m~7m (Passive) / 15m (Active)
Data Rate 10G/25G/40G/100G/400G 10G/25G/40G/100G
Power Consumption Low Lower (Passive DAC has almost no power consumption)
Interference Resistance Strong, less affected by electromagnetic interference Weak, easily affected by EMI
Weight Light Heavy
Cost Higher Lower
Application Scenarios Long-distance high-performance computing, data center interconnects Short-distance connections within or between racks

 

How to Choose?
Choose AOC: When you need long-distance transmission, low latency, and strong anti-interference (e.g., data center interconnections).
Choose DAC: When you need short-distance connections, cost-effectiveness, and interference resistance is not a major concern (e.g., server-to-switch connections).

 

For example：

Huawei QSFP-100G-AOC 5M

https://www.telecomate.com/qsfp-100g-aoc-5m/

QSFP-100G-AOC-5M-1

Huawei QSFP-40G-CU1M

https://www.telecomate.com/qsfp-40g-cu1m/

QSFP-40G-CU1M

When to Use SFP with a Patch Cable

If flexibility in choosing transceivers and cables is needed, such as in environments with anticipated future upgrades
In scenarios with both copper and fiber cabling infrastructure, using SFP modules with appropriate patch cables allows easy integration
For custom cable lengths or future upgrades to higher data rates, SFP+ with patch cables provides greater versatility

Summary

If your application is within a rack or for short-distance connections, DAC is the more economical choice. If you need longer transmission distances with better signal quality, AOC is the better option!