HP 670759-B25 FDR / 56GbE QSFP+ Passive Copper Cable, 3m: This is a 3-meter passive copper QSFP+ to QSFP+ Direct Attach Cable (DAC) carrying HP P/N 670759-B25, supporting up to 56Gb/s VPI for either FDR InfiniBand or 56GbE Ethernet. It is a fixed-length factory-terminated assembly, not a transceiver-and-patch-cord pair. This is a new unit.
Engineering Context
Passive copper DACs draw zero power from the host port and add only nanosecond-class propagation delay, making them the preferred choice for short rack-internal interconnects when reach is sufficient. The 670759-B25 carries 4 lanes of 14Gb/s NRZ over heavy-gauge twinax copper to deliver 56Gb/s aggregate. EMI-resistant by virtue of full-shielded twinax construction. No optics to clean and no AOC engine to fail. The HP P/N 670759-B25 is HP's branded equivalent of an FDR-class Mellanox-built cable assembly.
Deployment & Use Cases
Top-of-Rack to compute node interconnect on FDR-era HP ProLiant servers using HP InfiniBand FDR adapters. Storage-attached fabric uplinks at 56Gb/s. ConnectX-3 / ConnectX-3 Pro VPI HCA to FDR InfiniBand switch links. Spine-to-leaf 56GbE Ethernet between adjacent racks. HPC short-reach scale-out where the run is under 3m.
Technical Specifications
OEM: HP (HP P/N 670759-B25)
Form Factor: QSFP+ to QSFP+
Data Rate: Up to 56Gb/s VPI (4x14Gb/s NRZ)
Cable Type: Passive Copper Direct Attach (DAC)
Length: 3 meters
Protocols: FDR InfiniBand, 56GbE Ethernet (VPI)
Power Draw: 0W (passive)
Underlying Assembly: Mellanox-built FDR-class twinax
Connector Lock: Pull-tab QSFP+
Condition: New
Compatibility & Hard Constraints
Designed for HP ProLiant servers using HP InfiniBand FDR adapters and for FDR-era HP / Mellanox-based switches that accept the 670759-B25 P/N on their compatibility list. Compatible with QSFP+ ports rated for 14Gb/s per lane. Not compatible with QSFP28 100GbE ports — those use 25Gb/s per lane signaling. Not compatible with SFP+ or SFP28 ports without a breakout (no breakout is provided here). Fixed 3m length — no field-length adjustment. Verify HP-equivalence acceptance with non-HP host firmware before relying on the OEM P/N for compatibility-list certification.
Why Choose T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS verifies cable continuity, twinax shield integrity, and connector latch on every 670759-B25 prior to dispatch. See tes-itsolutions.com for cross-reference questions, multi-unit pricing, and 1–3 day handling on stocked items.