DAC cable CBO Q28-4S28-DAC-3M QSFP28 to 4× SFP28 direct-attach copper, 3 m

Direct-attach copper (DAC) cable CBO Q28-4S28-DAC-3M QSFP28 to 4× SFP28 direct-attach copper, 3 m provides a pre-terminated, fixed-length copper connection that links one QSFP28 port to four SFP28 ports over a 3-meter distance. Designed for short-reach, high-bandwidth interconnects in data centers and telecom racks, the cable supports 25GbE/100GbE equipment and enables aggregation or breakout of a 100GbE QSFP28 port into four 25GbE SFP28 channels. The compact form factor and integrated connectors simplify installation and reduce cabling complexity in switch-to-server, switch-to-switch, or switch-to-storage topologies.

Advantages

This DAC cable delivers low latency and low power consumption compared with active optical or active copper solutions, while offering a cost-effective option for high-density rack connectivity. Its pre-terminated construction eliminates on-site termination and ensures consistent electrical performance across all four SFP28 lanes. The direct-attach design provides reliable mechanical alignment and reduces cable management overhead in crowded rack environments.

Suitable for

• Breakout of a 100GbE QSFP28 port into four independent 25GbE SFP28 links
• Short-reach server-to-switch or switch-to-switch connections within data center racks
• High-density top-of-rack or end-of-row interconnects where low latency is required
• Environments seeking a low-power, cost-efficient alternative to active optical cables

Key specifications

• Connector type: one QSFP28 plug to four SFP28 plugs
• Length: 3 meters
• Media: direct-attach copper (passive copper cable)
• Supported data rates: compatible with 25GbE per lane and 100GbE aggregated operation
• Usage: short-reach interconnect for top-of-rack and in-rack cabling
• Form factor: pre-terminated, fixed-length breakout cable

How to use

Insert the QSFP28 end into the 100GbE QSFP28 port and plug each SFP28 connector into the corresponding 25GbE SFP28 ports. Ensure devices are powered down or that hot-plugging is supported by your equipment before insertion or removal to avoid link disruption. Verify port negotiation and speed settings on connected switches or servers; some platforms may require enabling breakout mode or specific firmware settings to recognize the 4×25GbE lanes. Route the cable to minimize strain and avoid sharp bends, keeping the cable within recommended bend radii for copper assemblies.

Recommendations

Use this cable for short-distance connections within the same rack or adjacent racks. For longer spans or where electrical interference is a concern, consider active optical alternatives. Check device compatibility and firmware requirements for QSFP28-to-4×SFP28 breakout functionality before deployment.