Twinax vs DAC Cable: What's the Difference?

 

Twinax vs DAC Cable: What's the Difference?

In high-speed data center environments, Twinax and Direct Attach Copper (DAC) cables are often mentioned interchangeably—but they’re not exactly the same. Understanding their distinctions helps in selecting the right connectivity solution for your Cisco ACI fabric or any modern network deployment.

🔌 Twinax Cable

• Definition: Twinax (short for twin axial) is a type of cable that uses two conductors within a single shielded cable to transmit differential signals.
• Use Case: It’s the physical medium used in many short-range, high-speed connections, especially in data centers.
• Form Factor: Twinax is the underlying cable technology used in DAC cables.

🔗 DAC Cable (Direct Attach Copper)

• Definition: DAC is a complete cable assembly that includes Twinax cabling with integrated transceivers at both ends (usually SFP+, QSFP+, or QSFP28).
• Use Case: Commonly used for short-distance connections between switches, servers, and storage devices—typically up to 7 meters.
• Types:
• Passive DAC: No signal amplification; ideal for short distances (up to ~5m).
• Active DAC: Includes signal conditioning electronics; supports slightly longer distances (up to ~10m).

🆚 Key Differences

Feature	Twinax Cable	DAC Cable
Definition	Cable type with twin conductors	Cable assembly with connectors
Includes Transceivers	❌ No	✅ Yes
Application	Used inside DAC or other assemblies	Plug-and-play for switch/server links
Distance Support	Depends on implementation	Typically 1–10 meters