400G QSFP56-DD DAC Cables

Direct and Breakout Copper Interconnects for AI and HPC

Overview

The 400G QSFP-DD Direct Attach Copper (DAC) cable portfolio provides a fast, simple, and cost-efficient way to deploy high-bandwidth connections in modern data centers. Built with passive twinax copper and QSFP-DD connectors, these cables deliver 400 Gbps of throughput over 8×50G PAM4 lanes, combining low latency, near-zero power draw, and simplified cabling into one solution.

With standard lengths up to 3 m (10 ft), NS 400G DACs are ideal for in-rack and rack-to-rack deployments where ultra-high performance is required over short distances. Optimized for NVIDIA/Mellanox platforms, these cables are also validated with select devices from Cisco, Juniper, Arista, Dell, and Huawei, ensuring versatile deployment options.

Broad Compatibility

NS 400G DACs are designed for NVIDIA-driven AI and HPC environments, delivering optimal performance in GPU-intensive clusters. In addition, they offer limited interoperability with Cisco, Juniper, Arista, Dell, and Huawei, giving network operators confidence when deploying DACs in diverse ecosystems.

Product Range

• QSFP-DD to QSFP-DD DAC
  Provides direct 400G-to-400G connectivity between core switches or between servers and switches, with uncompromised stability and minimal latency.

• QSFP-DD to 2×QSFP56 DAC
  Splits one 400G port into two independent 200G QSFP56 connections, ideal for scaling modular network topologies.

• QSFP-DD to 4×QSFP56 DAC
  Breaks down a 400G port into four 100G QSFP56 links, delivering flexible options for aggregation and access networks.

• QSFP-DD to 8×SFP56 DAC
  Converts one 400G port into eight 50G SFP56 connections, maximizing port utilization in high-density environments.

Key Benefits

• Ultra-high bandwidth: Full 400 Gbps transmission over 8×50G PAM4 lanes.

• Multiple configurations: Available in direct attach, 1:2, 1:4, and 1:8 breakout designs.

• Ultra-low latency: Electrical copper signaling ensures immediate response.

• Energy efficiency: Passive design consumes virtually no power.

• NVIDIA-optimized: Designed for GPU-driven workloads, with interoperability across select other platforms.

Buying Guide

• By type:

  • Choose QSFP-DD to QSFP-DD for direct 400G connections.

  • Select 1:2 breakout for dual 200G interconnects.

  • Choose 1:4 breakout for flexible 100G aggregation.

  • Use 1:8 breakout for dense 50G access environments.

• By length: Best suited for 1–3 m short-distance connections inside or between racks.

• By application: Perfect for AI/ML clusters, HPC workloads, and hyperscale data center fabrics.

• Ask for advice: For multi-vendor environments, consult our team to confirm compatibility.

Conclusion

The 400G QSFP-DD DAC Collection combines high bandwidth, flexible breakout options, and NVIDIA optimization to deliver powerful short-range interconnects. With direct and breakout configurations, low power usage, and proven reliability, NS DACs provide the essential building blocks for next-generation AI, HPC, and data center networks.

⚡ Choose NS 400G DACs to simplify your cabling, reduce costs, and achieve reliable high-speed connectivity today.