Dell DAC-Q56DD-400G-3M Compatible 400G QSFP-DD 8 x 50G PAM4 Passive Copper Twinax Cable, 3m (10ft)

This 3m (10ft) DAC-Q56DD-400G-3M compatible assembly provides 400G DAC connectivity for Dell interfaces in a QSFP-DD to QSFP-DD configuration. It is supplied as one complete cable, with specifications and installation guidance that help high-density racks balance reach, connector access and airflow while retaining the exact OEM reference required by the host.
OEM Part Number: DAC-Q56DD-400G-3MHT Part Number: DAC-Q56DD-400G-3M
Product Highlights
- Compatible alternative to Dell DAC-Q56DD-400G-3M
- 400G connectivity at 400Gbps
- Interface configuration: QSFP-DD to QSFP-DD
- Fixed length and part number: 3m (10ft), DAC-Q56DD-400G-3M
- Cable construction: Passive Twinax
- Conductor specification: 26AWG
- Maximum power consumption: 0.1W Per End
- Minimum bend radius: 57mm
Specifications
| HT Part Number | DAC-Q56DD-400G-3M |
|---|---|
| Dell(DE) Compatible | DAC-Q56DD-400G-3M |
| Manufacturer | HT |
| Form Factor | QSFP-DD to QSFP-DD |
| Max. Data Rate | 400Gbps |
| Media | Copper |
| Cable Type | Passive Twinax |
| Cable Length | 3m (10ft) |
| Wire AWG | 26AWG |
| Minimum Bend Radius | 57mm |
| Max. Power Consumption | 0.1W Per End |
| Jacket Material | PET |
| Commercial Temperature Range | 0 to 70°C (32 to 158°F) |
| Modulation Format | 8x 50Gbps PAM4 |
| Application | 400G Ethernet |
| Protocols | IEEE 802.3cd, QSFP-DD MSA, CMIS 4.0 |
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.
High-Density Rack Integration
In a densely populated rack, connector access and airflow are part of the link design. Choose the shortest length that follows the managed path comfortably, avoid tight bundles around the connector housings and preserve room for latch operation. Where power consumption is listed, include every populated interface in the host thermal budget rather than assessing a single cable in isolation. For this assembly, the listed conductor specification is 26AWG; the minimum bend radius is 57mm; the stated power consumption is 0.1W Per End; the jacket material is PET.
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 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.
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
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.
Position Within the Length Range
DAC-Q56DD-400G-3M is the longest of 6 verified length options in this family. Compared with DAC-Q56DD-400G-2.5M 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.
Quality Assurance and Packaging
Each assembly receives a visual connector inspection and functional link check before it is coiled and protected. Packaging is selected to avoid compressing the cable into a tight bundle, and optional rack-based labels help maintain an orderly installation when many identical interfaces are populated together. Standard protective packing is used by default, with project documentation arranged when requested.
Ordering Information
Provide the exact part number, length, quantity and target interface density. For multi-rack projects, list each length separately and identify any preferred carton grouping. Host model and software information can be included for a compatibility review before production or dispatch. Keep DAC-Q56DD-400G-3M associated with 3m (10ft) throughout the order and receiving record.
Dell Compatibility and Factory Testing
The assembly is evaluated for host recognition and stable link operation, with diagnostics checked where the interface provides them. This approach verifies more than electrical or optical continuity. Exact platform and firmware information remains valuable in high-density deployments because port mode and qualification policy can differ within the same connector family. Where supported by the host, link stability and diagnostic indications are reviewed together with the established link.
Frequently Asked Questions
Is this an original Dell cable?
No. It is an HT-manufactured compatible alternative for equipment that specifies Dell DAC-Q56DD-400G-3M.
How should an unused assembly be stored?
Protect both connector ends, keep the cable in a loose bend-safe coil and retain its part-number label so the length and compatibility identity remain traceable.
Can different brands be connected with the same assembly?
Only where both hosts explicitly support the complete interface and compatibility arrangement. Document each end and select the appropriate brand-specific product when required.
Does this order code cover multiple lengths?
No. DAC-Q56DD-400G-3M refers here to 3m (10ft). Every other verified length has a separate part number and page in the length list.
Shipping and Lead Time
Standard configurations normally ship within one to three working days, with production quantities confirmed at order stage. 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.
DAC-Q56DD-400G-3M