DAC cable CBO QSFP28 to 4×SFP28, passive, 3 m

Passive Direct Attach Copper (DAC) cable CBO QSFP28 to 4×SFP28, 3 m, is a short-reach, high-bandwidth breakout cable designed to convert a single QSFP28 100GbE port into four independent SFP28 25GbE links. Constructed for reliable rack-level connections, this passive copper assembly provides low latency and low power consumption without requiring external transceivers. The 3 m length is intended for top-of-rack and middle-of-row installations where cost-efficient, high-speed connectivity is needed between switches, servers and storage systems.

Advantages

The cable delivers four 25GbE channels from a single QSFP28 connector using passive copper wiring, minimizing complexity and eliminating the need for optical modules. Its passive design reduces power draw and heat compared with active assemblies, while maintaining signal integrity for short distances. The breakout format simplifies migration and port consolidation in data centres by enabling direct connection of SFP28 ports to a QSFP28 uplink without additional optics.

Suitable for

• Top-of-rack and spine switch to server connections
• Server to storage or NIC breakout links
• Short-reach 100GbE to 4×25GbE breakout applications
• Racks and rows in data centre aggregation layers

Key specifications

• Connector type: QSFP28 to 4×SFP28 breakout
• Cable type: Passive direct attach copper (DAC)
• Supported speeds: 100GbE native, convertible to 4×25GbE
• Length: 3 meters
• Form factor: Breakout cable for rack-level connectivity
• Typical use range: Short-reach interconnects within racks or between adjacent racks

How to use

Insert the QSFP28 plug into the 100GbE QSFP28 port on the switch or aggregation device and insert each SFP28 plug into corresponding 25GbE ports on servers, NICs or storage appliances. Ensure both ends are fully seated and secured by the connector latches. Verify link status and speed via the network equipment management interface and configure port mapping or breakout modes if required by the switch firmware. No additional optics or power sources are required for passive operation.

Recommendations

Use this passive QSFP28 to 4×SFP28 DAC for short-distance, high-bandwidth links within a rack or between adjacent racks. Avoid installation in environments that exceed typical data centre temperature ranges, and route the cable to prevent sharp bends or kinks. For longer reaches or environments requiring optical isolation, consider active DACs or fiber solutions.