D-Link DEM-CB100Q28-4S28 100G QSFP28 to 4 SFP28 Breakout Cable

A Direct Connection for a Planned High-Speed Rack The DEM-CB100Q28-4S28 is a passive copper direct attach cable for supported high-speed network equipment. A QSFP28 connector at one end connects to four SFP28 ends, supporting four 25GbE lanes when the host is configured for the correct breakout mode. Its factory-terminated one-metre assembly suits a short, deliberately planned rack connection. Integrated connectors remove the need to buy separate optical modules and fibre leads for this copper link. Confirm both host models, supported firmware and cable compatibility before deployment. The cable does not convert an incompatible port, provide arbitrary speed negotiation or replace the port configuration required by the equipment. Highlights Connection Layout 1 × QSFP28 to 4 × SFP28. 4 × 25GbE with supported 100G breakout mode. Fixed 1 m factory-terminated passive copper assembly. Rack Planning 30 AWG twinaxial construction. No separate optical transceivers or fibre leads needed for this link. Confirm exact host compatibility at both ends. Physical Specification Minimum bend radius 23 mm. Operating temperature −40°C to 75°C. 5-year warranty. Key Features A Factory-Terminated Copper Link The integrated connectors and twinaxial copper cable form one assembly. This provides a straightforward short rack connection without selecting separate optical modules and fibre leads. It is a direct attach cable, not an RJ-45 patch lead or an optical transceiver that can be separated from the cable. Understand the Port Layout One QSFP28 end breaks out to four SFP28 ends. The parent port must explicitly support four 25GbE breakout operation and be configured accordingly. The cable alone cannot make an unsupported 100G port split into four independent links. Match Both Host Devices Check each switch or adapter model and its current cable compatibility list. Supported firmware, port settings and vendor coding can matter even when the connectors fit. Avoid treating a general form-factor match as a guarantee that the connection will work with unrelated equipment. Route the One-Metre Assembly Allow for the path between ports, cable management and safe connector access. The factory length is one metre and cannot be extended by ordinary fibre adapters. Keep bends at or above the specified 23 mm minimum radius. Avoid tension on the connectors and leave service access in the rack. Passive Construction for a Short Distance The passive assembly is intended for supported short copper links. It does not have a separate mains power adapter and is not a solution for long-distance fibre runs. Choose an optical connection instead when the distance, electrical environment or host requirements call for fibre. Commission Before Depending on the Link Confirm link speed and error counters after installation, then test the traffic path required by the application. Label the four branch ends so the breakout mapping remains clear during maintenance. Follow the equipment vendor’s insertion and removal instructions and protect connector contacts from contamination. Summary The DEM-CB100Q28-4S28 is a fixed one-metre passive DAC for supported 100G-to-four 25G breakout connections. Match the hosts, port mode and rack route before selecting the assembly. Frequently Asked Questions What Connectors Does It Have?ExpandCollapse One QSFP28 connector and four SFP28 connectors. Does It Require Breakout Support?ExpandCollapse Yes. The QSFP28 host must support and be configured for four 25GbE breakout operation. The cable cannot add this function to an unsupported port. What Is the Cable Length?ExpandCollapse This offer is the fixed 1 m factory assembly. Allow for routing and the minimum bend radius when planning the rack. Are Separate Optical Modules Needed?ExpandCollapse No. This copper DAC has integrated connectors. It does not use separate optical modules or fibre patch leads. Will It Work With Any Brand?ExpandCollapse Do not assume universal compatibility. Check both exact host models, firmware and supported cable lists. Can It Be Used for a Long Fibre Run?ExpandCollapse No. It is a short passive copper assembly. A suitable optical module and fibre system are needed for a longer optical connection. Magbasa pa