DAC cable CBO Q28-4S28-DAC-3M-NK-BL 3 m QSFP28 100 Gbit/s

Direct attach copper (DAC) cable CBO Q28-4S28-DAC-3M-NK-BL is a 3 m QSFP28 passive copper assembly designed for 100 Gbit/s short-reach connections. It provides a direct electrical link between QSFP28 ports on switches, servers and network adapters, delivering low-latency, high-throughput connectivity for dense rack environments and adjacent rack connections in data centres.

Advantages

The cable offers a compact, low-power alternative to active optical modules for short distances, with predictable latency and simplified deployment. Built for 100 Gbit/s operation over a 3 m reach, it reduces cabling complexity and eliminates the need for separate transceivers, enabling cost-effective scaling of top-of-rack and aggregation links. Its QSFP28 form factor ensures compatibility with standard QSFP28 ports and supports high-density installations.

Suitable for

• Interconnection between top-of-rack switches and adjacent rack switches
• Direct server-to-switch or server-to-server links supporting 100 Gbit/s
• High-performance computing clusters and storage networks requiring low latency
• Short-reach connections in hyperscale and enterprise data centres

Key specifications

• Connector type: QSFP28 to QSFP28 passive copper
• Data rate: 100 Gbit/s
• Length: 3 metres
• Cable type: Direct attach copper (passive DAC)
• Primary use: Short-reach interconnects within racks and between adjacent racks
• Latency: low, electrical transmission
• Form factor: QSFP28 compatible for high-density ports

How to use

Insert each QSFP28 end of the cable into the corresponding QSFP28 port until the connector latch engages. Ensure both ports are powered and configured for a 100 Gbit/s link on the connected devices. Monitor link status via the network equipment interface and verify negotiation and error counters during initial setup. For removal, depress the latch and withdraw the connector straight out to avoid damage to the port or cable.

Recommendations

Place the cable to avoid sharp bends and maintain the minimum bend radius specified for copper assemblies. Use in environments with appropriate airflow and temperature control for data centre equipment. For runs beyond the recommended short-reach distance, consider active copper or optical transceivers. Verify compatibility with switch and server vendor QSFP28 port guidelines before deployment.