Cisco QDD-400-CU3M Compatible 400G QSFP-DD 8 x 50G PAM4 Passive Copper Twinax Cable, 3m (10ft)

For short, high-density connections, this DAC cable combines 400G performance with a fixed 3m (10ft) cable run. It corresponds to Cisco QDD-400-CU3M and uses a factory-terminated passive copper link without separate optical modules or patch cords.

OEM Part Number: QDD-400-CU3MHT Part Number: QDD-400-CU3M

Product Highlights

• Compatible alternative to Cisco QDD-400-CU3M
• 400G connectivity at 400Gbps
• Interface configuration: QSFP-DD to QSFP-DD
• Fixed length and part number: 3m (10ft), QDD-400-CU3M
• Cable construction: Passive Twinax
• Conductor specification: 26AWG
• Maximum power consumption: 0.1W Per End
• Minimum bend radius: 57mm

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.

At 3m (10ft), this assembly can bridge non-aligned ports or adjacent racks while remaining a single direct-attach link. Support longer horizontal runs with suitable cable management and preserve space for cooling and future maintenance.

QDD-400-CU3M is the longest of 6 verified length options in this family. Compared with QDD-400-CU2.5M at 2.5m (8ft), it provides 0.5m of additional reach for a longer vertical drop, a wider rack or an adjacent-cabinet route. Confirm that the complete path requires this length, because unused slack still needs supported, bend-safe storage.

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.

This assembly uses 26AWG conductors, PET jacket, minimum bend radius 57mm. 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.

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.

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.

Our compatibility setup for Cisco QDD-400-CU3M is checked together with the physical 3m (10ft) assembly. Factory verification covers connector condition, host identification, error-free link establishment and electrical continuity, link stability and diagnostic readouts. Providing the exact host model and firmware release helps us identify platform-specific requirements before production.

Use part number QDD-400-CU3M for the 3m (10ft) assembly. For mixed-length projects, list each required part number and quantity separately so that every cable can be tested and packed according to its intended installation.

Every QDD-400-CU3M compatible assembly undergoes link testing, compatibility verification and visual inspection. The 3m (10ft) cable is coiled without exceeding its minimum bend radius, fitted with connector protection and packed in an anti-static bag or protective tray before cartoning. Project labels and packing lists are available for volume orders.

Available stock is usually packed and handed to the carrier within one to three working days. Delivery can be arranged by international express, air cargo or sea freight, with tracking details supplied after dispatch. Freight-collect shipments and delivery to a customer warehouse or forwarder can also be coordinated.