InfiniBand/fibre optic cable BlueOptics Q28-4S28-DAC-3M-AT-BL 3m QSFP28 4xSFP28 Male/Male

The BlueOptics Q28-4S28-DAC-3M-AT-BL is a 3 m QSFP28 to 4xSFP28 direct attach cable (DAC) designed for high-speed InfiniBand and Ethernet connections in rack and adjacent-rack installations. This passive twinax copper breakout cable supports aggregated 100G data rates (4x25G lanes) and provides a compact, low-latency link between QSFP28 ports and four SFP28 ports. The male-to-male connector configuration and MSA-compliant mechanical and electrical interfaces ensure interoperability with hardware that supports QSFP28 breakout DACs.

Advantages

The cable offers low power consumption typical of passive DACs, minimal latency and predictable signal integrity for short-reach interconnects. With 26 AWG twinax construction and MSA-compliant QSFP28/SFP28 interfaces, it provides a reliable, mechanically robust connection suitable for data center top-of-rack and adjacent-rack links. Tested component selection and manufacturing processes are used to maintain compatibility and service life suitable for professional network deployments.

Suitable for

• High-speed connections between QSFP28 ports and multiple SFP28 ports in switches and routers
• Top-of-rack (ToR) and adjacent-rack wiring in data centers
• Server to switch or switch to storage system short-reach links
• InfiniBand and Ethernet applications up to 100 G aggregated bandwidth over 3 m

Key specifications

• Length: 3 meters
• Connector configuration: QSFP28 (male) to 4 × SFP28 (male)
• Supported protocols: 100GBase-CR4 / 4×25GBASE-CR, InfiniBand compatible
• Cable type: Passive twinax copper (DAC)
• Wire gauge: 26 AWG
• MSA compliance: QSFP28 breakout DAC mechanical and electrical specifications
• Typical use case range: short-reach rack/adjacent-rack connections

How to use

Install by inserting the QSFP28 end into a compatible QSFP28 port and each SFP28 plug into the corresponding SFP28 ports on the target device. Ensure both devices support passive QSFP28-to-SFP28 breakout DACs and the intended link speed and protocol. Route the cable to avoid sharp bends and mechanical strain; use proper cable management to maintain bend radius and prevent connector stress. Power off or follow hot-plug procedures per device documentation if required by your hardware vendor before insertion or removal.

Recommendations

Verify device compatibility with QSFP28 breakout DACs in vendor documentation and, if available, test a sample in your target hardware before large deployments. Keep the cable within recommended bend radius, avoid exposure to moisture or corrosive environments, and use in short-reach applications where passive DACs are supported to benefit from low latency and low power consumption.