Cisco QDD-400-CU1M Compatible 400G QSFP-DD 8 x 50G PAM4 Passive Copper Twinax Cable, 1m (3ft)

Use the QDD-400-CU1M compatible assembly where a 400G connection is required between compatible ports. This page covers the 1m (3ft) version only, with its own HT part number, specifications and compatibility verification.

OEM Part Number: QDD-400-CU1MHT Part Number: QDD-400-CU1M

Product Highlights

• Compatible alternative to Cisco QDD-400-CU1M
• 400G connectivity at 400Gbps
• Interface configuration: QSFP-DD to QSFP-DD
• Fixed length and part number: 1m (3ft), QDD-400-CU1M
• Cable construction: Passive Twinax
• Conductor specification: 30AWG
• Maximum power consumption: 0.1W Per End
• Minimum bend radius: 33mm

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.

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.

At 1m (3ft), QDD-400-CU1M is a practical choice for direct connections within one rack. Route the cable along the intended management path rather than pulling it diagonally across adjacent connectors, and leave enough clearance for insertion, removal and front-panel airflow.

QDD-400-CU1M occupies the middle of this family between QDD-400-CU0.5M at 0.5m (2ft) and QDD-400-CU1.5M at 1.5m (5ft). It adds 0.5m over the shorter option for extra routing clearance, while the next longer version adds another 0.5m. Measure the managed path and choose this version when its reach is sufficient without creating the slack associated with the longer assembly.

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 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.

The assembly is configured for equipment that recognizes QDD-400-CU1M. Before shipment, we inspect both connectors and verify identification, link establishment and electrical continuity, link stability and diagnostic readouts. Host hardware and firmware revisions can affect third-party cable acceptance, so customers can provide the equipment model and software release for a pre-order compatibility review.

Use part number QDD-400-CU1M for the 1m (3ft) 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.

Production inspection covers both physical condition and a live link check. Connector ends receive individual protection, and the completed assembly is packed without tight ties or sharp bends. For multi-length projects, cartons can be separated and labelled by OEM part number to simplify installation on site.

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.