OCuLink Cable Assemblies
OCuLink is the compact high-speed interface used for internal and near-system PCIe and storage connectivity. It is the family most often specified when a straight slot-to-device path is not physically available.
On this page
- What is the difference between SFF-8611 and SFF-8612?
- What OCuLink lane widths are available?
- What does an OCuLink cable connect?
- What should you confirm before specifying an OCuLink cable?
- What OCuLink assemblies does EPS build to specification?
- What information does EPS need to quote an OCuLink cable?
- Frequently asked questions
What is the difference between SFF-8611 and SFF-8612?
SFF-8612 is the connector specification. It defines the mating interface — plug and receptacle mechanicals, contact positions, keying, latching, and the board footprint for the receptacle. Anything with an OCuLink port soldered to a board is built to SFF-8612: an adapter, an add-in card, a backplane, a motherboard.
SFF-8611 is the cable assembly specification. It builds on the SFF-8612 plug and adds what a finished cable needs — assembly-level electrical performance (insertion loss, return loss, crosstalk and impedance), wire and lane assignments for PCIe and SAS use, and assembly construction detail.
The two are not alternatives. A compliant OCuLink cable assembly mates to an SFF-8612 receptacle and is itself built to SFF-8611. Where a drawing calls out one number, it is usually indicating which side of that boundary it governs.
What OCuLink lane widths are available?
OCuLink is built in 4i and 8i. The number is the lane count; "i" denotes internal.
What does an OCuLink cable connect?
Host boards, adapter cards, backplanes, storage devices and other internal high-speed endpoints. The common pairings run OCuLink to U.2 (SFF-8639) drives and OCuLink to SlimSAS (SFF-8654), in both straight and Y-cable topologies, and in straight, right-angle and low-profile orientations.
What should you confirm before specifying an OCuLink cable?
- Do not assume MCIO and OCuLink are interchangeable. Separate families; validate both endpoints.
- The connector alone does not prove generation support, lane mapping or endpoint compatibility.
- Do not assume active retiming or redriving. Active signal conditioning applies only where explicitly specified.
- Do not assume the host or backplane supports the intended topology unless documented or validated.
- Orientation is part of the specification — straight, right-angle and low-profile are different parts.
What OCuLink assemblies does EPS build to specification?
EPS manufactures OCuLink assemblies to your specification in Acton, Massachusetts, prototype through production — 10 to 10,000-plus units, QC tested. Length, conductor size and color, stranding, shielding (foil, braid or combination), jacket material (PVC, TPU, FEP, LSZH), temperature and environmental rating, overmolded boots, strain reliefs, latching systems and custom contact configurations are all specified by you. Y cables and mixed-endpoint harnesses are built to the topology you specify.
Lead time depends on the specification and the volume, and we confirm it with your quote.
Looking for a stocked part rather than a custom build? See available OCuLink cables at MicroSATACables.
What information does EPS need to quote an OCuLink cable?
- What exact connector is on each end — OCuLink 4i, 8i, U.2, SlimSAS, or something else?
- Is the path PCIe expansion or storage?
- What generation and lane-count target matters?
- What orientation is required — straight, right-angle, low-profile?
- Is a Y cable or a specific internal routing required?
Frequently asked questions
What is OCuLink?
A compact high-speed cabling interface used for internal or near-system connectivity in storage and PCIe deployments.
What is the difference between SFF-8611 and SFF-8612?
Both are identified as OCuLink standards. The catalog applies SFF-8611 to cable assemblies and SFF-8612 to adapters and add-in cards. If your drawing calls out one specifically, tell us which.
What lane widths does OCuLink come in?
4i and 8i. The "i" denotes internal.
Can OCuLink connect to a U.2 drive?
Yes — OCuLink to U.2 (SFF-8639) is one of the common pairings, in both straight and Y-cable topologies.
Is OCuLink the same as MCIO?
No. They are separate interconnect families and are not interchangeable without exact endpoint validation.
Have a custom interconnect challenge that off-the-shelf parts won’t solve?
EPS engineers and manufactures precision cable assemblies, signal-conditioning AICs, and custom enclosures for OEM partners, in Acton, Massachusetts. Lead time is confirmed with your quote against the actual specification and volume.