Cisco QDD-4ZQ100-CU0.5M Compatible 400G QSFP-DD 8 x 50G PAM4 to 4 x 100G QSFP56 2 x 50G PAM4 Passive Copper Breakout Cable, 0.5m (2ft)

Product Highlights

• Compatible alternative to Cisco QDD-4ZQ100-CU0.5M
• 400G connectivity at 400Gbps
• Interface configuration: QSFP-DD to 4x QSFP56
• Fixed length and part number: 0.5m (2ft), QDD-4ZQ100-CU0.5M
• Conductor specification: 30AWG
• Maximum power consumption: 0.1W (QSFP-DD End)0.1W (QSFP56 Per End)
• Minimum bend radius: 35mm
• Operating temperature: 0 to 70°C (32 to 158°F)

Specifications

Signal and Lane Configuration

The listed modulation format is QSFP-DD-8x 50G-PAM4QSFP56-2x 50G-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 (QSFP-DD End)0.1W (QSFP56 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, PVC jacket, minimum bend radius 35mm. 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 SFF-8665, QSFP-DD MSA, IEEE802.3bj, IEEE802.3 cd. Confirm that the host firmware and port configuration support the same operating mode.

Breakout Port Mapping

The QSFP-DD to 4x QSFP56 configuration divides the high-speed interface into multiple lower-speed connections. Verify the upstream lane assignment, downstream port speeds and breakout setting on the host before connecting the assembly. Each branch must attach to the correct remote interface.

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-4ZQ100-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-4ZQ100-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-4ZQ100-CU1M at 1m (3ft), adding 0.5m for a less direct routing path; selecting it unnecessarily would leave more cable to dress.

Data-Center Design and Airflow

Select the assembly by both reach and rack layout. A direct connection removes separate module-and-patch-cord interfaces, but it still needs a bend-safe pathway and clear connector access. Keep cable bundles from blocking front-panel airflow, account for the listed interface power where applicable and choose a length that supports maintenance without leaving an unmanaged coil. For this assembly, the listed conductor specification is 30AWG; the minimum bend radius is 35mm; the stated power consumption is 0.1W (QSFP-DD End)0.1W (QSFP56 Per End); the jacket material is PVC.

Quality Assurance and Packaging

Each cable receives connector inspection and a functional link check before it is coiled with bend-safe slack and packed. Protective materials shield the connector housings during transport. Rack or project labels are available to keep length, part number and installation destination aligned. Neutral packaging and customer-specific packing documentation are available on request.

Ordering Information

Provide the OEM reference, HT part number, fixed length and quantity, together with the intended host interfaces. Rack-based quantities and packaging instructions can be included for larger deployments. Other lengths are separate products and should be entered on their own order lines. Quantity and any labeling instructions should be attached specifically to QDD-4ZQ100-CU0.5M.

Cisco Compatibility and Factory Testing

Compatibility confirmation combines host identification with actual link establishment and diagnostic checks. The assembly is prepared for the stated OEM reference rather than selected only by connector shape. For a new data-center deployment, the equipment model, port mode and software release provide the most useful basis for a pre-order review. Where supported by the host, link stability and diagnostic indications are reviewed together with the established link.

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.