Cisco QDD-400-CU0.5M Compatible 400G QSFP-DD 8 x 50G PAM4 Passive Copper Twinax Cable, 0.5m (2ft)

Product Highlights

• Compatible alternative to Cisco QDD-400-CU0.5M
• 400G connectivity at 400Gbps
• Interface configuration: QSFP-DD to QSFP-DD
• Fixed length and part number: 0.5m (2ft), QDD-400-CU0.5M
• Cable construction: Passive Twinax
• Conductor specification: 30AWG
• Maximum power consumption: 0.1W Per End
• Minimum bend radius: 33mm

Specifications

Signal and Lane Configuration

The listed modulation format is 8x 50Gbps PAM4. Both host interfaces must be configured for the same aggregate rate and lane arrangement. A connector that fits mechanically does not by itself guarantee that the remote port supports this encoding or breakout mode.

Power and Thermal Planning

The rated power consumption is 0.1W Per End. Include this load in the host-port power and thermal budget, especially in densely populated switches. Maintain front-panel clearance and do not bundle the cable so tightly that it obstructs airflow around the connectors.

Cable Construction and Routing

This assembly uses 30AWG conductors, PET jacket, minimum bend radius 33mm. These mechanical characteristics affect how the cable should be dressed behind the equipment. Avoid sharp edges, excessive ties and repeated tight bends close to the connector boots.

Network and Protocol Considerations

The intended application is 400G Ethernet. Listed interface and protocol references include IEEE 802.3cd, QSFP-DD MSA, CMIS 4.0. Confirm that the host firmware and port configuration support the same operating mode.

Passive Copper Operation

A passive DAC has no separate optical conversion stage. Its low-power, low-latency operation is useful for short equipment links, but the assembly must remain within the length and signaling mode accepted by both hosts.

Length Selection and Installation Planning

The 0.5m (2ft) length is suited to closely aligned ports where excessive slack would obstruct airflow or complicate dressing. Measure the actual port-to-port path before choosing QDD-400-CU0.5M; even a short assembly must retain the specified bend radius and should never be pulled tight behind the equipment.

Position Within the Length Range

QDD-400-CU0.5M is the shortest of 6 verified length options in this family. It is the preferred choice when the port positions are close and cable slack must be kept to a minimum. The next option is QDD-400-CU1M at 1m (3ft), adding 0.5m for a less direct routing path; selecting it unnecessarily would leave more cable to dress.

Mixed-Vendor Network Operation

A mixed-vendor link should be documented at both ends, not treated as one generic connection. Confirm which OEM identity each host expects and whether the two ends use the same compatibility requirement. The related brand links below help locate equivalent-length assemblies, while the physical form factor and lane arrangement must still agree across the complete path. For this assembly, the listed conductor specification is 30AWG; the minimum bend radius is 33mm; the stated power consumption is 0.1W Per End; the jacket material is PET.

Cisco Compatibility and Factory Testing

Testing addresses the brand-specific identification as well as the operating link and available diagnostics. The same physical cable family can require a different host identity for another equipment vendor, so the intended platform should be supplied when a deployment combines multiple brands or unusual hardware revisions. Where supported by the host, link stability and diagnostic indications are reviewed together with the established link.

Ordering Information

For mixed-vendor projects, identify the equipment at both ends along with the OEM reference, length and quantity. Order each compatibility version under its own part number. If spare assemblies are required, list them separately so labels and test records remain unambiguous. Quantity and any labeling instructions should be attached specifically to QDD-400-CU0.5M.

Quality Assurance and Packaging

Both ends are inspected and the complete assembly is powered up for a functional check before packing. Connectors are protected individually and the cable is secured without tight bends. Optional labels can distinguish host brand, OEM reference and length for easier spares management. Standard protective packing is used by default, with project documentation arranged when requested.

Frequently Asked Questions

Shipping and Lead Time

Available stock is generally dispatched within one to three working days after order confirmation, with production lead times advised for larger quantities. International express, air cargo and sea freight can be selected according to destination and carton volume; customer courier accounts and nominated forwarders are also accepted.