OCuLink Cable Assemblies
OCuLink is a compact PCIe cable system defined by two SFF specifications: SFF-8611 for the cable assemblies and SFF-8612 for the shielded connector, both in four- and eight-lane sizes. It carries PCIe between boards, drive bays and enclosures, and has found a second use linking small computers to external GPUs and PCIe docks. PCI-SIG's newer CopprLink specification is positioned as its successor. OCuLink lines are quoted as built to your drawing or sourced by part number.
Where OCuLink assemblies are used
Server NVMe and accelerators
OCuLink to U.2 drives or accelerator cards on platforms that expose OCuLink ports.
External GPUs and PCIe docks
Shielded four-lane links from a mini PC or embedded board to an external graphics or PCIe enclosure.
Embedded and industrial systems
Compact PCIe cabling between boards in small enclosures where a slot will not fit.
What you can specify
Each point is confirmed with our manufacturing partner before the quotation. Connectors are the genuine parts your drawing names, and an alternative is used only with your written approval.
- x4 or x8 at each end
- The far end: OCuLink, U.2, Mini SAS HD, SlimSAS or MCIO
- Length, and straight or right-angle plugs
- Sideband lines per the host's pin map
- Inside the case or outside it, and the jacket that suits
Testing and records
Assemblies built to your drawing are continuity tested unit by unit and ship with a test report; sourced cables ship as supplied by their maker. Signal-integrity data such as insertion loss or impedance is never assumed: if your link needs it, say so in the RFQ, and whether and how it can be measured is confirmed before the quotation.
Every PCIe lane and sideband contact is checked end to end on each cable, whatever sits at the far end.
How testing and records work →How long can the cable be?
Sum the PCIe channel the way the specifications budget it, host package to device, and read the margin a given length, wire gauge and host trace leave at Gen4, Gen5 or Gen6. Every figure is sourced on the page and can be replaced with your own.
Open the MCIO / SlimSAS insertion loss calculator →Common questions
Can OCuLink be used outside the case?
Yes — the SFF-8612 connector is shielded, and OCuLink is used for external GPU and PCIe enclosures. Cable length and the host's PCIe generation decide whether the link trains reliably, so put both in the RFQ.
Is OCuLink being replaced by CopprLink?
PCI-SIG positions CopprLink, released in 2024, as the successor, and its internal cable is built on the SFF-TA-1016 (MCIO) connector family. OCuLink ports remain on many boards and docks in service, and cables for them are still made.
What should an OCuLink cable RFQ include?
The width at each end, both connector types, length, the PCIe generation, inside or outside the case, the host and device models, and quantities.
Related connectors
Industries
Connector and series names on these pages — JST, Molex, Micro-Fit, Mini-Fit, PicoBlade, Pico-Lock, CLIK-Mate, PCIe, MCIO, SlimSAS, OCuLink, HSD, HFM and DEUTSCH among them — may be trademarks of their respective owners. They are used only to identify the connectors an assembly is built with or mates with. Interconnix is not affiliated with, sponsored by or an authorized distributor of any connector maker.