Network Cable BlueOptics DAC-Q28-S28-2M-BL QSFP28 4xSFP28 InfiniBand 2m Black

The BlueOptics DAC-Q28-S28-2M-BL is a 2 m direct-attach cable (DAC) designed for short-reach high-speed interconnects in data centres and rack environments. One end features a QSFP28 connector and the other end breaks out to four SFP28 connectors, enabling 100GBase-CR4 to 4x25GBASE-CR connectivity over twinax copper. The cable is a passive, MSA-compliant twinax assembly with 26 AWG conductors and a black outer jacket. It is intended for use where electrical short-distance links are preferred over active optical transceivers and supports Ethernet, FCoE, Fibre Channel and InfiniBand protocols when used with compatible hardware.

Advantages

The cable provides a cost-effective, low-latency connection for short distances with low power consumption due to its passive twinax design. MSA compliance and the QSFP28 to 4xSFP28 breakout enable flexible deployment between 100G ports and multiple 25G ports without additional transceivers. Built with industry-grade components and 26 AWG conductors, the assembly is suitable for dense rack installations and is designed for consistent performance and long operational life when used within the intended distance and supported platforms.

Suitable for

• Connecting QSFP28 100G ports to four 25G SFP28 ports within the same rack or adjacent racks
• High-density switch-to-switch and switch-to-server connections in data centres
• Short-reach InfiniBand, Ethernet, FCoE or Fibre Channel links up to 2 m
• Environments where low latency and low power consumption are required

Key specifications

• Cable length: 2 m
• Connector configuration: QSFP28 to 4 × SFP28
• Cable type: Passive twinax copper (DAC)
• Conductor gauge: 26 AWG
• Supported data rates/protocols: 100GBase-CR4 / 4×25GBASE-CR, compatible with Ethernet, FCoE, Fibre Channel and InfiniBand over short distances
• Product colour: Black
• Typical use: Rack and adjacent rack interconnects

How to use

Ensure that both devices explicitly support passive QSFP28 to 4×SFP28 direct-attach twinax cables and that firmware/driver requirements for passive DACs are met. Power down or place interfaces in a safe state if recommended by your equipment vendor, insert the QSFP28 connector into the 100G port and then connect the four SFP28 connectors to the corresponding 25G ports. Verify link status on each port and confirm negotiated speeds and protocols through your switch or host management interface. Avoid sharp bends and excessive strain on the cable and secure routing within rack channels or cable management panels.

Recommendations

Use this passive DAC for short, high‑bandwidth links inside racks or between adjacent racks. For longer distances or where optical isolation is required, select active optical cables or transceiver plus fibre solutions. Regularly inspect connector contacts and cable routing to maintain signal integrity and expected lifetime.