Direct Attach Copper (DAC) Cable CBO QSFP28-DAC-0.5M 0.5 m Passive QSFP28 to QSFP28

Passive Direct Attach Copper (DAC) cable CBO QSFP28-DAC-0.5M is a 0.5 m twinax cable with QSFP28 connectors at both ends, intended for short-reach 100GbE connections. The BlueOptics cable offers a direct electrical connection between QSFP28 ports without separate optical transceivers, enabling a compact, low-latency link for top-of-rack and adjacent-rack interconnects in data centres, server racks and high-density networking environments.

Advantages

This passive QSFP28 to QSFP28 cable provides a cost-effective alternative to active modules for short-distance 100 Gigabit Ethernet links. Its fixed 0.5 m length minimises signal loss and crosstalk typical for longer copper runs, and the twinax construction supports stable high-speed transmission with low latency. The design eliminates the need for separate transceivers, reducing power consumption and simplifying inventory management for deployments with multiple short links.

Suitable for

• Short-reach 100GbE connections between switches and servers
• Top-of-rack to adjacent-rack interconnects in data centres
• Direct attach links between network interface cards (NICs) and QSFP28 ports
• High-density rack environments where low latency and compact cabling are required

Key specifications

• Connector type: QSFP28 to QSFP28
• Cable type: Passive twinax copper
• Length: 0.5 m
• Data rate: Designed for 100 Gigabit Ethernet
• Latency: Low-latency direct attach electrical link
• Power: Passive design; no active electronics in the cable

How to use

Insert each QSFP28 connector into the corresponding QSFP28 port on networking equipment such as switches, routers or server NICs, ensuring the latch engages correctly. Use the 0.5 m passive DAC for direct short links where both ends support QSFP28 electrical interfaces. Confirm port configuration and link speed in the device management interface; no additional transceiver configuration is required. For removal, press the connector latch or pull tab as specified by the equipment vendor and withdraw the cable straight out to avoid damaging the port.

Recommendations

Use this passive QSFP28 cable for stable, low-latency 100GbE connections within the same rack or adjacent racks. Avoid sharp bends and excessive tensile force on the cable, and maintain the recommended bend radius to preserve signal integrity. Verify compatibility with the host equipment’s supported QSFP28 passive DAC connections before deployment.