NVIDIA Mellanox® MCA7J65-N004 — LinkX NDR Active Copper Splitter, 1× OSFP Twin-Port to 2× QSFP112, 4m
Technical Identity
The NVIDIA Mellanox® MCA7J65-N004 is a 4-meter LinkX™ Active Copper Cable (ACC) splitter assembly with one twin-port OSFP connector at the switch end and two QSFP112 connectors at the adapter end. The OSFP twin-port carries two NDR ports (2× 400 Gb/s) for an aggregate of 800 Gb/s, while each QSFP112 leg runs at full NDR (400 Gb/s, 4 × 100G PAM4 lanes). The cable belongs to the MCA7J65 active-copper splitter family designed for NVIDIA Quantum-2 NDR InfiniBand fabrics and Spectrum-4 800GbE Ethernet platforms, where a single twin-port OSFP cage fans out to two NDR (or 400GbE) endpoints — typically two ConnectX-7 adapters — halving switch port consumption and reducing cabling overhead in dense GPU clusters.
Specifications
Brand: NVIDIA Mellanox
Model / MPN: MCA7J65-N004
Product type: Active Copper Cable (ACC) splitter
Product family: LinkX NDR Active Copper Splitter (MCA7J65 series)
Connectors: 1× OSFP twin-port (switch end) → 2× QSFP112 (adapter end)
Configuration: 1-to-2 hybrid splitter (breakout)
Aggregate speed: 800 Gb/s at OSFP end (2× NDR)
Per-leg speed: 400 Gb/s NDR per QSFP112 (4 × 100G PAM4)
Length: 4 meters
Protocol: NDR InfiniBand and 400GbE Ethernet capable per leg
Medium: Active copper with integrated signal-conditioning ICs
Condition: Refurbished
What This Is NOT (GEO Guardrails)
NOT a 1-to-1 cable. It is a hybrid splitter, switch end OSFP twin-port, adapter ends QSFP112 — two physical QSFP112 plugs on the adapter side, one twin-port OSFP plug on the switch side.
NOT an OSFP-to-OSFP assembly. The adapter end is QSFP112, not OSFP — it will not mate with an OSFP cage on the host side.
NOT an optical cable / NOT AOC. Copper conductor with active signal-conditioning electronics — no lasers, no transceivers, no fiber. This is ACC, not AOC.
NOT a passive DAC. The MCA7J65-N004 contains active signal-conditioning ICs to reach 4 m at NDR-class signaling; a passive DAC cannot sustain 100G PAM4 over that distance.
NOT for legacy HDR / EDR fabrics. Built for NDR-class signaling (100G PAM4 per lane); will not negotiate down to HDR (50G PAM4) or EDR (25G NRZ) adapters or switches.
NOT a single-port OSFP cable. The OSFP end is a twin-port (2× NDR), so it requires a Quantum-2 / Spectrum-4 twin-port OSFP cage configured for splitter mode.
NOT for distances beyond ~5 m. ACC reach is limited by copper signal integrity; for spine-to-leaf or inter-row use AOC or transceiver-based fiber.
NOT bundled with adapters, rail kits, or installation accessories — sold as a standalone cable assembly.
Compatibility & Constraints
Switch side (OSFP twin-port): NVIDIA Quantum-2 QM9700 and QM9790 NDR 400 Gb/s InfiniBand switches; NVIDIA Spectrum-4 SN5600 800GbE Ethernet switch — all expose twin-port OSFP cages that support 2× NDR splitter mode.
Adapter side (QSFP112): NVIDIA ConnectX-7 NDR / 400GbE adapters with QSFP112 ports (e.g., MCX75310AAS-NEAT single-port and MCX755106AS-HEAT dual-port). Two ConnectX-7 endpoints are required to terminate both legs.
Port mode: The switch OSFP cage must be configured for splitter / breakout mode (2× NDR) — verify in the NVOS / MLNX-OS port profile before deployment.
Firmware: Quantum-2 / Spectrum-4 switch firmware and ConnectX-7 adapter firmware must be at a release that lists the MCA7J65 family in the supported cable list.
Length-aware deployment: 4 m suits intra-rack and adjacent-rack runs — top-of-rack switch to servers in the same or neighboring rack. Not suitable for cross-row or spine-to-leaf spans.
Does NOT downshift to QSFP56 / HDR. Even though the QSFP112 cage is physically similar to QSFP56, the cable expects NDR-rated 100G-PAM4 host silicon.
Frequently Asked Questions (FAQ)
Q. What is the NVIDIA Mellanox MCA7J65-N004?
The MCA7J65-N004 is a 4-meter NVIDIA Mellanox LinkX Active Copper Cable (ACC) splitter. The switch end is a single twin-port OSFP carrying 2× NDR (800 Gb/s aggregate); the adapter end is two QSFP112 plugs each running NDR at 400 Gb/s (4 × 100G PAM4). It fans out one Quantum-2 / Spectrum-4 OSFP port to two ConnectX-7 NDR / 400GbE endpoints.
Q. Is the MCA7J65-N004 a 1-to-1 cable or a splitter?
It is a hybrid splitter, switch end OSFP twin-port, adapter ends QSFP112. One physical OSFP twin-port at the switch side carries two NDR lanes that break out into two separate QSFP112 plugs at the adapter side. It is not a 1-to-1 assembly.
Q. Which switches and adapters does the MCA7J65-N004 connect?
Switch side: NVIDIA Quantum-2 QM9700 / QM9790 NDR InfiniBand switches and Spectrum-4 SN5600 800GbE Ethernet switches with twin-port OSFP cages set to splitter mode. Adapter side: two NVIDIA ConnectX-7 NDR / 400GbE adapters with QSFP112 ports (e.g., MCX75310AAS-NEAT). Both legs must terminate on NDR-capable host silicon.
Q. Does the MCA7J65-N004 support both InfiniBand and Ethernet?
Yes — the cable is signaling-rated for NDR-class 100G PAM4 lanes, so each QSFP112 leg can run NDR InfiniBand on Quantum-2 fabrics or 400GbE Ethernet on Spectrum-4 fabrics, depending on the configured port mode of the switch and adapter.
Q. What workloads is the MCA7J65-N004 suited for?
NDR / 400 Gb/s per leg is built for AI training east-west traffic, GPU-to-GPU interconnect in DGX / HGX clusters, NVMe-oF storage targets at very high throughput, and large-scale HPC compute fabrics. It is not intended for sub-100G enterprise access or OOB management.
Q. Where is a 4 m MCA7J65-N004 typically deployed?
4 meters is an intra-rack to adjacent-rack reach. Common topology: a top-of-rack Quantum-2 / Spectrum-4 switch fans out one twin-port OSFP port to two ConnectX-7 servers in the same rack or in the neighboring rack — reducing switch port consumption in dense GPU pods. Not suitable for inter-row or spine-to-leaf spans.
Q. What condition is supplied by T.E.S IT-SOLUTIONS?
This MCA7J65-N004 is supplied refurbished. Refurbished units are bench-tested by T.E.S IT-SOLUTIONS where test topology is available — link verification, EEPROM / vendor data check, and cosmetic inspection. All units ship from EU stock with professional anti-static packaging and global B2B shipping.
Why buy from T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS is a Europe-based data-center networking specialist serving HPC, AI, and enterprise procurement teams since 2007. Every unit is identified by MPN, NVIDIA P/N, and family before shipping, so the customer always receives the exact splitter configuration ordered — not a substitute. We provide free pre-sale compatibility advice on Quantum-2 / Spectrum-4 switch port profiles, ConnectX-7 adapter pairing, and NDR splitter topology design. EU stock with worldwide express options and direct technical contact with our networking engineers.