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

The BlueOptics Q28-4S28-DAC-2M-AT-BL is a 2 m direct-attach twinax cable with a QSFP28 connector on one end and four SFP28 connectors on the other. Designed for short-reach, high-speed links in racks and between adjacent racks, this passive 100GBase-CR4 / 4x25GBASE-CR twinax cable delivers electrical 100 Gbit/s connectivity when used with hardware that supports QSFP28 breakout to 4x25G SFP28. The cable is black, lightweight (approx. 0.25 kg) and MSA-compliant for interoperability with a wide range of switches, routers and storage systems from major vendors.

Advantages

This direct attach cable provides low-latency, low-power connectivity for short-distance, high-bandwidth applications. As a passive twinax assembly it does not require external power or transceivers, reducing power consumption and potential points of failure. MSA-compliant electrical and mechanical design ensures compatibility with equipment that supports QSFP28-to-4xSFP28 breakout configurations, and the compact 2 m length is suited to rack-to-rack or intra-rack connections.

Suitable for

• High-speed breakout links: QSFP28 to 4x25G SFP28 connections
• Data centre rack-to-rack or intra-rack connections
• 100G Ethernet, FCoE, Fibre Channel and InfiniBand short-reach links
• Switches, routers and storage systems that support passive DAC twinax cabling

Key specifications

• Cable length: 2 m
• Connector A: QSFP28 (male)
• Connector B: 4 × SFP28 (male)
• Transmission: passive twinax for up to 100 Gbit/s (QSFP28 breakout to 4 × 25 Gbit/s)
• Conductor gauge: 26 AWG (typical for twinax DAC)
• Product colour: Black
• Approx. weight: 0.25 kg
• MSA-compliant QSFP28 breakout DAC

How to use

Install the BlueOptics Q28-4S28-DAC-2M-AT-BL by inserting the QSFP28 plug into the QSFP28 port of the source device and the four SFP28 plugs into the corresponding SFP28 ports of the destination device or devices. Ensure both ends are fully seated and that the host hardware supports passive DAC breakout operation and the intended protocol (e.g., 100GBase-CR4 or 4x25GBASE-CR). No external power or transceivers are required. After connection, verify link status and speed via the equipment management interface and monitor for any error counters during initial operation.

Recommendations

If used in data centre environments, keep the cable length suitable for the intended deployment (2 m for close rack or adjacent-rack links), avoid tight bends or excessive pulling force, and connect only to hardware that officially supports passive QSFP28-to-4xSFP28 DACs to ensure full functionality and reliability.