The JBX05031 400GBASE-CR8 QSFP-DD to 4x QSFP56 direct attach copper cable represents a cost-effective, high-performance solution for modern data center infrastructure requiring 400 Gigabit Ethernet connectivity. This 2-meter passive breakout cable is fully compatible with Cisco's QDD-4ZQ100-CU2M specification, providing drop-in replacement functionality for existing deployments. **Technical Specifications & Architecture** Built with premium 28AWG twinax copper conductors and flame-retardant plastic jacketing, this cable delivers exceptional signal integrity across the full 2-meter length. The QSFP-DD form factor connector aggregates four independent QSFP56 connections, enabling the breakout of one 400G port into four separate 100G lanes—a critical capability for flexible network architectures. **Standards Compliance & Certification** This cable is rigorously qualified to ETC 400GBASE-CR8 specifications and adheres to QSFP-DD MSA (Multi-Source Agreement) standards. Full RoHS (Restriction of Hazardous Substances) and ELV (End of Life Vehicle Directive) compliance ensures environmental responsibility. UL and TUV safety certifications validate electrical safety and performance under diverse operating conditions (0-70°C operating temperature range). **Passive Design Advantages** Unlike active cables requiring external power, this passive direct attach solution operates without power consumption, reducing overall system complexity and operating costs. This makes it ideal for high-density data center environments where power management and thermal considerations are critical. **Application Use Cases** • Enterprise data centers requiring 400G-to-100G breakout architecture • Cloud service providers consolidating rack connectivity • High-performance computing (HPC) clusters • Storage networks demanding low-latency, high-bandwidth links • Network virtualization and software-defined infrastructure **Value Proposition** Compared to optical solutions, direct attach copper cables eliminate transceiver costs and optical module inventory complexity. The Cisco compatibility ensures seamless integration with existing infrastructure investments. At 2 meters, this cable length covers typical intra-rack and adjacent-rack scenarios without excessive slack. **Warranty & Support** Backed by a 90-day limited warranty, this cable includes the assurance of quality manufacturing. Ships from US locations (Danville, CA and Beaufort, SC) with free standard shipping on orders exceeding $99. **Specifications Summary** • Cable Type: Passive Breakout DAC • Connector Configuration: QSFP-DD to 4x QSFP56 • Length: 2 meters • Gauge: 28AWG • Material: Copper with plastic jacketing • Data Rate: 400GB • Standards: 400GBASE-CR8, QSFP-DD MSA, CMIS • Compliance: RoHS, ELV, UL, TUV • Operating Temperature: 0-70°C (32-158°F) • OEM Replacement: Cisco QDD-4ZQ100-CU2M Custom brand programming is available for organizations requiring proprietary branding on network infrastructure. This cable represents the optimal balance of performance, compatibility, and cost-effectiveness for 400G breakout applications.