The JBX05039 3-meter 400GBASE-CR8 QSFP-DD breakout cable represents a cost-effective and reliable solution for enterprise-grade data center networking. As a direct replacement for Cisco's QDD-4ZQ100-CU3M, this passive direct attach copper (DAC) cable delivers exceptional performance without the complexity and expense of active solutions. **Technical Excellence** This cable utilizes 28AWG twinax copper conductors housed in durable plastic jacketing, providing optimal signal integrity for high-speed 400GB Ethernet transmission. The QSFP-DD to 4x QSFP56 configuration enables single-lane to multi-lane connectivity, making it ideal for disaggregated network architectures and flexible switch port utilization. **Specifications & Compliance** Manufactured to strict 400GBASE-CR8 standards and qualified to ETC specifications, the JBX05039 maintains full compliance with RoHS, ELV, and TUV certifications. With an operating temperature range of 0-70°C and compact dimensions (12x12x3mm), it integrates seamlessly into standard data center environments. **Application & Use Cases** Ideally suited for rack-to-rack connections in modular switch architectures, this breakout cable is essential for organizations requiring flexible port configurations without sacrificing performance. Common applications include cloud data centers, high-frequency trading environments, and enterprise network backends. **Quality Assurance** Backed by a 90-day limited warranty and engineered with premium copper connectors, the JBX05039 delivers reliable long-term performance. Custom brand programming is available for enterprise deployments. **Shipping & Support** Available with free standard shipping on orders over $99, this cable ships from multiple US locations (Danville, CA and Beaufort, SC), ensuring rapid delivery. Its passive design eliminates power consumption concerns and reduces operational costs compared to active alternatives. Invest in high-performance data center connectivity with the JBX05039—the intelligent choice for 400G infrastructure.