InfiniBand/fibre optic cable BlueOptics Q28-4S28-DAC-1M-AT-BL 1m QSFP28 4xSFP28 Male/Male

The BlueOptics Q28-4S28-DAC-1M-AT-BL is a 1 metre passive direct attach cable (DAC) with a QSFP28 connector on one end and four SFP28 connectors on the other, designed for short-reach, high-speed InfiniBand and Ethernet links. It supports 100GBase-CR4 or 4x25GBASE-CR electrical interfaces and is intended for use in rack-to-rack and intra-rack connections where low latency and high throughput are required. The cable is built to MSA-compliant form factors and uses 26 AWG twinax construction suitable for professional data centre hardware that accepts QSFP28 to 4xSFP28 breakout DACs.

Advantages

This BlueOptics QSFP28 to 4xSFP28 DAC provides low-latency, low-power connectivity for short-distance links without active transceivers. Passive twinax construction reduces power consumption and failure points compared with active optical modules. The breakout design enables a single 100G port to be split into four independent 25G channels for flexible network topologies. MSA-compliant mechanical and electrical characteristics ensure interoperability with major switch, router and storage platforms that support QSFP28 breakout DACs.

Suitable for

• Rack-to-rack and adjacent-rack high-speed links in data centres
• Connecting QSFP28 switch ports to multiple 25G SFP28 ports
• Short-reach InfiniBand and Ethernet applications (100GBase-CR4 / 4x25GBASE-CR)
• High-density top-of-rack deployments and server interconnects

Key specifications

• Cable type: Passive twinax direct attach cable (DAC)
• Length: 1 metre
• Connector A: QSFP28 (male)
• Connector B: 4 × SFP28 (male)
• Supported protocols: 100GBase-CR4 and 4×25GBASE-CR (Ethernet), compatible with InfiniBand signaling
• Wire gauge: 26 AWG
• Form factor: QSFP28 breakout to 4×SFP28, MSA-compliant
• Typical use: short-distance, rack/inter-rack connections with low latency

How to use

Install the cable by inserting the QSFP28 end into the 100G QSFP28 port and the four SFP28 ends into the respective 25G SFP28 ports, ensuring each connector clicks into place. Confirm that the host hardware supports passive QSFP28-to-4xSFP28 breakout DACs and that firmware or driver settings allow operation at the intended rates. Use the cable for links up to 1 metre; avoid bending the cable beyond the manufacturer’s minimum bend radius and ensure connectors remain free of dust and debris.

Recommendations

For reliable operation, verify compatibility with your switch, router or HBA vendor and, if possible, test a sample in your environment before wide deployment. Keep the cable secured to avoid strain on the connectors and maintain ambient operating temperatures specified by your networking equipment.