Cisco QDD-400G-4QAC Compatible 400G QSFP-DD 8 x 50G PAM4 to 4 x 100G QSFP56 2 x 50G PAM4 Active Copper Breakout Cable

The QDD-400G-4QAC compatible series is designed for Cisco hosts requiring a 400G ACC connection. Its QSFP-DD to 4x QSFP56 arrangement is supplied as an active copper assembly with the cable and signal-conditioning interfaces supplied together. Use the specifications to assess the physical assembly, then follow the exact length and part-number links when preparing a bill of materials or requesting a compatibility check.
Series Part Number: QDD-400G-4QACHT Part Number: QDD-400G-4QAC
Product Highlights
- HT-manufactured compatible alternative for Cisco QDD-400G-4QAC
- 400G aggregate connectivity at 400Gb/s
- Interface configuration: QSFP-DD to 4x QSFP56
- Active Twinax
- Length configurations covered: 3m (10ft) and 5m (16ft)
- Conductor specification: 30 AWG
- Power consumption: <0.1W
Available Lengths and Corresponding Part Numbers
The documented series configuration is 3m (10ft) and 5m (16ft). Use the relevant OEM reference below together with the HT identity and required length when requesting a quotation. If another length carries a different OEM part number, it must be reviewed and ordered as that distinct configuration.
Compatible OEM Part Numbers
- QDD-400G-4QAC03
Specifications
| HT Part Number | QDD-400G-4QAC |
|---|---|
| Manufacturer | HT |
| Form Factor | QSFP-DD to 4x QSFP56 |
| Max Data Rate | 400Gb/s |
| Cable Length Options Covered | 3m (10ft) and 5m (16ft) |
| Cable Type | Active Twinax |
| Minimum Bend Radius | 70mm |
| Wire AWG | 30 AWG |
| Jacket Material | PVC |
| Power Consumption | <0.1W |
| Modulation Format | PAM4 |
| Inbuilt FEC | No |
| Operating Temperature Range | 0 to 70°C (32 to 158°F) |
| Inbuilt FEC | QSFP-DD MSASFF-8679SFF-8636 |
Applications and Deployment
Active copper assemblies add signal conditioning while retaining the convenience of a direct-attached cable. They are appropriate where the equipment supports the stated active-cable type and the route exceeds the practical limits of a comparable passive assembly. Per-end power, airflow and host qualification should be assessed before high-density deployment. For this series, the listed interface is QSFP-DD to 4x QSFP56 and the aggregate rate is 400G.
Cisco Compatibility and Factory Testing
Verification covers the physical connectors, expected host identity and an operating link with available diagnostic indications. We distinguish this complete check from a simple continuity test. Platform model and software release can be reviewed in advance where the installation has strict documentation or change-control requirements. Series-level inspection is followed by the exact length and OEM configuration selected for dispatch. Functional verification includes link establishment and diagnostic indications where the host exposes them.
Cable Construction and Routing
For this assembly, the conductor specification is 30 AWG; the jacket material is PVC; the minimum bend radius is 70mm; the power consumption is <0.1W. These parameters belong in the installation review rather than being treated as catalogue trivia. Route the cable through its intended managers without tension, avoid pressure close to the connector boots and leave enough space to operate the latches. Any service loop must respect the stated bend limit.
Structured Pathways and Serviceability
Treat the direct-attach assembly as part of the permanent pathway plan even when the link is expected to be temporary. Follow the intended horizontal and vertical managers, maintain the specified bend radius and leave service access around both ports. A small, supported service allowance is preferable to excess slack concealed inside a rack or placed under cable-tie pressure. For this series, keep the interface rate, ACC construction and length-specific OEM reference together throughout that review.
Ordering Information
Include the part number, fixed length, quantity and required pathway or rack grouping in the order information. The host model and firmware release are useful for change-controlled deployments. Different lengths should remain separate order lines so delivered labels and packing records agree with the pathway plan. For this series, follow the corresponding length link, quote that exact OEM part number and keep different lengths on separate order lines. HT part number QDD-400G-4QAC identifies the product family; the linked page provides the final length-specific identity.
Shipping and Lead Time
Standard configurations normally ship within one to three working days, with production lead times confirmed for larger quantities. International courier, air freight and sea freight are available; customer courier accounts and nominated forwarders are accepted.
Quality Assurance and Packaging
After connector inspection and link verification, the assembly is coiled without tight bends and packed with end protection. Labels can cross-reference the customer cable schedule, OEM part number and length. This supports both receiving checks and later moves, adds or changes. Both connector ends are inspected as part of the complete assembly, and protective packing is selected to avoid tight bends during transport and storage.
Frequently Asked Questions
Is this an original Cisco cable?
No. It is an HT-manufactured compatible cable for equipment that specifies QDD-400G-4QAC, not an original Cisco-branded product.
Are different lengths and OEM part numbers separate products?
Yes. Where a length has its own OEM reference, follow the corresponding link above and order that exact part number on its own line. Do not substitute another length only because the connector arrangement is the same.
Does this ACC cable require separate modules at each end?
No. The connector ends and cable form one complete direct-attach assembly. The ends are not detachable standalone transceivers, and the complete product is tested together.
What information helps confirm compatibility?
Provide the equipment manufacturer and model, port type, hardware revision and software release, together with the required OEM reference, length and quantity. Breakout projects should also identify the intended lane configuration.
10/100BASE-T SFP