DAC cable CBO QSFP28 to 4×SFP28 passive, 3 m, BlueLAN

BlueOptics DAC cable QSFP28 to 4×SFP28 passive, 3 m (BlueLAN) is a direct-attach copper breakout cable designed to connect one QSFP28 port to four independent SFP28 ports. Intended for short-reach interconnects inside racks and between adjacent network devices, this passive assembly supports splitting a single 100GbE interface into four 25GbE links without active transceivers or optical modules. The cable combines compact form factor and energy-efficient passive wiring to deliver low-latency connectivity for data center switches, routers and servers that support breakout mode.

Advantages

The passive DAC design eliminates the need for separate optical transceivers, reducing component count, power consumption and heat generation. A 3 m length provides flexibility for common rack topologies while minimizing excess cable slack. The QSFP28-to-4×SFP28 breakout arrangement simplifies cabling when converting a 100GbE port to multiple 25GbE links, enabling straightforward aggregation or distribution of bandwidth. The cable’s copper construction and passive characteristics offer predictable latency and reliable electrical performance for short-distance links.

Suitable for

• Data center top-of-rack and end-of-row connectivity
• Splitting a 100GbE interface to four 25GbE host ports
• Connecting servers, switches and routers that support QSFP28 breakout
• Short-reach interconnects inside racks or between adjacent cabinets

Key specifications

• Interface: one QSFP28 plug to four SFP28 plugs
• Length: 3 meters
• Type: passive direct-attach copper breakout cable
• Supported link rates: 100GbE to 4×25GbE (breakout mode)
• Latency: low, deterministic electrical path suitable for short-reach connections
• Construction: multi-conductor copper with molded connectors and strain relief

How to use

Install the cable by inserting the QSFP28 connector into the 100GbE port on the switch or router and connect each SFP28 plug to the corresponding 25GbE ports on target devices. Ensure both ends are fully seated and the devices are powered down or support hot-plugging according to vendor guidance. Configure the network equipment to enable QSFP28 breakout or port splitting so that the single QSFP28 interface presents four independent 25GbE links. Verify link status and speed in the device management interface after installation.

Recommendations

Use this passive DAC in short-distance, rack-level connections and in environments where the host devices explicitly support QSFP28-to-SFP28 breakout. Avoid routing the cable through long conduits or across large open pathways, and keep cable runs within recommended length limits to maintain signal integrity. Follow vendor guidelines for supported breakout modes and firmware compatibility when deploying these cables in production networks.