DAC cable CBO QSFP28-DAC-3M-PA-BL — QSFP28 3 m, 100 Gbit/s direct-attach

CBO QSFP28-DAC-3M-PA-BL is a 3-metre direct-attach copper (DAC) cable engineered for 100 Gbit/s links between QSFP28 ports. The passive copper assembly provides a point-to-point wired connection with minimal latency and low power consumption, intended for short-reach interconnects inside racks or across adjacent racks in data centre and enterprise networks. The cable is compatible with QSFP28 ports on switches, routers and network appliances that accept standard passive DAC modules.

Advantages

The DAC cable offers a cost-effective alternative to optical transceivers for short-distance 100 Gbit/s links, eliminating the need for separate SFP/QSFP optical modules and fibre patch cords. Passive construction reduces power draw compared with active optical solutions and introduces negligible signal processing delay, helping to maintain low latency for server-to-switch and switch-to-switch traffic. Its 3 m length provides a balance between reach and cable management within rack environments.

Suitable for

• Server-to-switch connections inside the same rack or neighbouring racks
• Short-distance switch-to-switch uplinks within data centre rows
• High-bandwidth appliance interconnects where 100 Gbit/s throughput is required
• Environments prioritising low latency and low power consumption

Key specifications

• Connector type: QSFP28 to QSFP28 direct-attach copper
• Length: 3 metres
• Nominal data rate: 100 Gbit/s (supporting aggregated 4x25G lanes)
• Construction: Passive copper twinax cable assembly
• Typical use: Short-reach, within-rack or adjacent-rack interconnects
• Latency: Minimal, passive signal path
• Power: Low power consumption compared with active optical modules

How to use

Insert each QSFP28 connector into the corresponding QSFP28 port until the latch clicks, ensuring correct alignment. Verify link negotiation and speed on connected devices according to their management interface or LEDs. For safe handling, avoid tight bends and excessive pulling on the cable; maintain manufacturer-recommended bend radius and secure the cable to reduce strain. If replacing or installing multiple DACs, perform one link at a time and confirm network status before proceeding to the next connection.

Recommendations

Use this passive DAC for short-distance 100 Gbit/s links inside racks or between adjacent racks. Confirm compatibility with the switch or appliance vendor’s supported transceiver list if firmware-based validation is enforced. Store and route the cable away from sources of electromagnetic interference and avoid repeated sharp bends to preserve signal integrity.