Cisco QSFP-H40G-CU0-5M
40GBASE-CR4 Passive Copper Cable, 0.5m, Original Cisco
Product Highlights
As data center densities increase and east-west traffic volumes surge, every interconnect matters. The Cisco QSFP-H40G-CU0-5M is a 40GBASE-CR4 passive direct-attach copper (DAC) cable that delivers reliable 40 Gigabit Ethernet connectivity over a 0.5-meter twinax copper assembly — ideal for short-reach, high-bandwidth links between switches, routers, and servers within the same rack or adjacent racks.
This QSFP+ to QSFP+ cable eliminates the need for separate transceivers and fiber patch cords, significantly reducing both cost and cabling complexity. As a passive cable, it requires no external power for signal transmission, keeping power budgets lean in high-density environments. The cable is hot-swappable, enabling seamless upgrades and replacements without network downtime.
Compliant with the QSFP+ Multi-Source Agreement (SFF-8436) and IEEE 802.3ba 40GBASE-CR4 standards, the QSFP-H40G-CU0-5M is a genuine Cisco product engineered for use across Cisco's 40GbE-capable switching and routing platforms. Whether you're building out a leaf-spine fabric, connecting compute nodes in an HPC cluster, or establishing high-speed storage area network links, this DAC cable provides the low-latency, high-throughput connectivity your infrastructure demands.
Features & Benefits
40 Gbps Passive Direct-Attach Copper
The QSFP-H40G-CU0-5M uses four fully duplex copper data lanes to deliver an aggregate 40 Gbps of bandwidth over a passive twinax assembly. Passive operation means no active electronics in the cable — resulting in ultra-low latency and minimal power draw, which is critical in dense data center environments where every watt and microsecond counts.
Simplified Cabling & Reduced Cost
Direct-attach copper cables combine the transceiver and cable into a single integrated assembly, eliminating the need to purchase separate QSFP+ optics and fiber patch cords. This reduces per-link cost, simplifies inventory management, and speeds up deployment — making DAC cables the preferred choice for short-reach 40GbE connections.
Hot-Swappable & Easy to Deploy
The cable is fully hot-swappable, allowing network engineers to install or replace it without powering down connected equipment. Simply plug the QSFP+ connectors into compatible ports and the link comes up automatically — no configuration changes required for the physical layer.
Industry-Standard Compliance
Fully compliant with the QSFP+ Multi-Source Agreement (SFF-8436) and IEEE 802.3ba 40GBASE-CR4 specifications, this cable meets rigorous industry standards for signal integrity, electromagnetic compatibility, and mechanical reliability. It is also CE and RoHS certified.
Deployment Scenarios
Top-of-Rack Switch Interconnects
Connect top-of-rack switches to aggregation or spine switches within the same cabinet. The 0.5m length is perfectly suited for intra-rack cabling, keeping cable runs tidy and airflow unobstructed while delivering full 40 Gbps throughput.
High-Performance Computing (HPC) Clusters
Link compute nodes and cluster switches at 40 Gbps with minimal latency. Passive DAC cables are favored in HPC environments where low, deterministic latency is essential for parallel processing workloads and inter-node communication.
Data Center Storage Connectivity
Establish high-speed connections between storage arrays and network switches for SAN or converged infrastructure deployments. The cost-effectiveness and reliability of DAC cables make them ideal for dense storage environments requiring many 40GbE links.
Lab & Testing Environments
Quickly stand up 40GbE test links between adjacent devices on a lab bench or in a staging rack. The short 0.5m length and plug-and-play operation make this cable perfect for rapid prototyping and validation scenarios.
General
Performance
Physical
Environmental
Compliance
Compatibility Notes
The QSFP-H40G-CU0-5M is an original Cisco cable designed for use in Cisco platforms equipped with QSFP+ ports supporting 40GBASE-CR4. Always verify transceiver compatibility with your specific platform and running software version using the Cisco Transceiver Compatibility Matrix before ordering.
Downloads & Resources
Frequently Asked Questions
| Part Number | Product | Key Difference |
|---|---|---|
| QSFP-H40G-CU1M | Cisco 40GBASE-CR4 Passive DAC, 1m | Same passive DAC technology but with 1-meter reach for slightly longer intra-rack or adjacent-rack runs. |
| QSFP-H40G-CU3M | Cisco 40GBASE-CR4 Passive DAC, 3m | Extends passive copper reach to 3 meters for inter-rack connections within the same row. |
| QSFP-H40G-CU5M | Cisco 40GBASE-CR4 Passive DAC, 5m | Maximum passive DAC length at 5 meters — suitable for cross-row connections in smaller data centers. |
| QSFP-H40G-ACU7M | Cisco 40GBASE-CR4 Active DAC, 7m | Active copper cable with built-in signal amplification for 7-meter reach when passive lengths are insufficient. |
