Identity & Definition
The NVIDIA Mellanox MCP1660-W003 is a 400GbE enterprise data center direct attach copper (DAC) cable in refurbished condition. This passive copper cable uses QSFP-DD connectors on both ends to deliver 400Gb/s aggregate bandwidth over a 3-meter reach. The MCP1660-W003 is a point-to-point DAC cable — it is NOT an active optical cable (AOC), NOT a splitter or breakout cable, and NOT a fiber optic transceiver module. The full NVIDIA ordering reference is 980-9I35Q-00W003 (OPN: MCP1660-W003E26).
Engineering Context
The MCP1660-W003 transmits data at 400Gb/s using eight lanes of 50Gb/s PAM4 signaling across its QSFP-DD interface, compliant with IEEE 802.3cd. The cable is constructed with 26AWG copper conductors and an LSZH (Low-Smoke Zero-Halogen) outer jacket for enhanced fire safety in enclosed rack environments. At 3 meters, the MCP1660-W003 is the longest passive DAC option in the MCP1660 series, providing maximum rack-to-rack flexibility without optical transceivers. As a passive assembly, it requires no external power and introduces minimal signal latency.
Deployment & Use Cases
The MCP1660-W003 is designed for short-to-mid range 400GbE connections between data center racks. Typical deployment scenarios include spine-to-leaf switch links in 400G Ethernet fabrics, server-to-switch uplinks for AI training clusters and HPC nodes, and storage-to-network connections in high-bandwidth NVMe-oF and RoCE environments. The 3-meter reach extends connectivity across adjacent racks within a row. It is suited for NVIDIA Spectrum-3 and Spectrum-4 switch platforms and ConnectX-6 Dx or ConnectX-7 adapter deployments.
Technical Specifications

Part Number (MPN): MCP1660-W003
NVIDIA P/N (OPN): 980-9I35Q-00W003 (MCP1660-W003E26)
Cable Type: Passive Direct Attach Copper (DAC)
Data Rate: 400Gb/s (400GbE)
Connector: QSFP-DD to QSFP-DD
Cable Length: 3 meters
Wire Gauge: 26AWG
Jacket Material: LSZH (Low-Smoke Zero-Halogen)
Signaling: 8x 50Gb/s PAM4 (IEEE 802.3cd)
Condition: Refurbished

Compatibility & Hard Constraints
The MCP1660-W003 requires 400GbE-capable QSFP-DD ports on both endpoints. It is NOT compatible with QSFP28 (100GbE) or QSFP56 (200GbE) port cages — the QSFP-DD connector has a dual-row pin layout that differs physically from single-row QSFP28/QSFP56 connectors. This cable does NOT support breakout operation; it provides a single 400Gb/s link. For shorter reaches in the same series, the MCP1660-W001 (1m, 30AWG) and MCP1660-W002 (2m, 26AWG) are available.
Why Choose T.E.S IT-SOLUTIONS
Every MCP1660-W003 cable sold by T.E.S IT-SOLUTIONS is lab-tested for link integrity and bandwidth compliance before shipment. Our team provides technical consultation on NVIDIA Mellanox cable compatibility, quantity availability, and deployment planning. Orders ship within 1–3 business days with worldwide delivery and protective packaging.