DAC cable CBO QSFP28 to 4× SFP28, direct attach copper, 3 m

Direct Attach Copper (DAC) cable CBO QSFP28 to 4× SFP28, 3 m is a fixed copper breakout cable designed to connect a single QSFP28 port to four SFP28 ports. The cable supports short-reach, high-speed connections in data center environments where 25Gb/s lanes from a QSFP28 interface are split across multiple SFP28 endpoints. With a 3 meter length, this DAC solution provides a low-latency, power-efficient link for switches, servers and storage systems requiring dense, reliable aggregation.

Advantages

This DAC cable offers low electrical latency and reduced power consumption compared with active optical alternatives for short links. Being a direct attach copper assembly, it simplifies connectivity without external transceivers and lowers total cost of ownership for rack-to-rack or top-of-rack deployments. The integrated breakout design enables consolidation of multiple 25Gb/s lanes from a single QSFP28 port into independent SFP28 connections, facilitating flexible port mapping and easier hardware upgrades.

Suitable for

• Top-of-rack switch to server connections requiring multiple 25Gb/s links
• Cross-rack aggregation in compact data center layouts
• High-density switch port consolidation where QSFP28 breakout is needed
• Short-reach interconnects between storage arrays and compute nodes

Key specifications

• Cable type: passive direct attach copper breakout
• Connectors: QSFP28 (one end) to 4 × SFP28 (other end)
• Aggregate data rate: supports four 25Gb/s lanes from a QSFP28 interface
• Length: 3 meters
• Use case: short-reach, within-rack or adjacent-rack connections
• Latency: low electrical latency suitable for high-performance switching
• Power: passive copper design with minimal additional power requirements

How to use

Insert the QSFP28 end into the source device port and the four SFP28 ends into the corresponding target ports on switches, servers or storage equipment. Ensure both ends are fully seated and that connected devices support QSFP28-to-SFP28 breakout operation and the desired 25Gb/s lane configuration. Verify link status in the devices’ management interfaces and, if required, configure port mapping or lane assignment according to network design. Handle the cable by the connector housings and avoid excessive bending of the copper assembly to maintain signal integrity.

Recommendations

For optimal performance, use this 3 m DAC cable for short-reach links inside racks or between adjacent racks, ensure device compatibility with QSFP28 breakout functionality, and avoid running the cable near strong electromagnetic interference sources. Regularly inspect connectors for contamination and secure cable routing to prevent mechanical strain.