540-BBJL: Dell Mellanox ConnectX-4 Lx Dual Port 25GbE SFP28 Network Daughter Card (rNDC)

Also listed as: 023H1C, 23H1C, MCX4121A-ACFT, ConnectX-4 Lx rNDC · made by NVIDIA

The Dell 540-BBJL is a Dell Mellanox ConnectX-4 Lx Dual Port 25GbE SFP28 Network Daughter Card (rNDC) delivering 25GbE network connectivity across 2x 25GbE SFP28 via Dell Proprietary rNDC Connector. Built with NVIDIA controller architecture, the 540-BBJL provides hardware offload acceleration and virtualization support for R740, R740XD, R640 enterprise servers.

Specifications

About the 540-BBJL

The Dell 540-BBJL is a Dell Mellanox ConnectX-4 Lx Dual Port 25GbE SFP28 Network Daughter Card (rNDC) engineered to deliver 25GbE network transmission across 2x 25GbE SFP28 over Dell Proprietary rNDC Connector. Powered by NVIDIA controller architecture on the 540-BBJL, it executes hardware-level protocol processing, RoCE, and SR-IOV virtualization while maintaining a thermal envelope of approximately 12W. In Dell's networking portfolio, 540-BBJL provides dedicated high-bandwidth fabric connectivity for clustered virtualization, network storage, and enterprise database hosts.

Compatibility

Engineered for Dell PowerEdge servers including R740, R740XD, R640, the 540-BBJL mounts directly into Rack Network Daughter Card (rNDC) locations. The 540-BBJL installs into a standard Dell Proprietary rNDC Connector expansion riser slot with matching bracket profile. Cabling the 540-BBJL requires 25GbE-rated media, including direct attach copper twinaxial assemblies, optical transceivers, or patch leads matched to its physical ports. Supported operating systems on the 540-BBJL include VMware ESXi, Red Hat Enterprise Linux, and Windows Server with native Dell drivers.

How to identify a genuine unit

Authentic Dell 540-BBJL units carry an identification label displaying DP/N 023H1C and NVIDIA model code MCX4121A-ACFT along with Dell regulatory marks. In iDRAC Network Devices inventory, the card registers under part number 540-BBJL with active link state, port MAC addresses, negotiated speed, and certified Dell firmware. Onboard physical indicators on the 540-BBJL provide link status and port activity monitoring.

Buying used

When purchasing a pre-owned 540-BBJL, examine the gold edge connector fingers for scratches, peeling contacts, or missing surface-mount capacitors. Ensure that the 540-BBJL PCIe mounting bracket (low-profile or full-height) is intact and properly aligned for chassis installation. Validate in iDRAC Lifecycle Controller that the 540-BBJL is recognized with certified Dell firmware and passes diagnostics under sustained 25GbE network traffic.

Fits these models

• Dell PowerEdge R740
• Dell PowerEdge R740xd
• Dell PowerEdge R640

Works together

How the Dell 540-BBJL connects to servers, storage and the network: 3 ways, with the hardware on each path.

Plan and size it

• Draw this setup in the topology planner mrplanb.com
• Add up rack power and space rack-density.com
• iSCSI explained mrplanb.com
• Virtualization storage Ledger: scored storage platforms mrplanb.com
• Network monitoring tools compared mrplanb.com
• Dell E-Lab Navigator (Dell interoperability) dell.com

Check compatibility with Dell

Before you buy, confirm the exact configuration against the vendor's own lists: firmware levels, operating systems, adapters and optics that Dell has tested with the Dell 540-BBJL.

• Compatibility Dell E-Lab Navigator (storage and SAN interoperability) (free vendor sign-in)
• Support Dell Support: drivers, manuals and service tag lookup

Equivalent part numbers

• NVIDIA MCX4121A-ACFT Mellanox ConnectX-4 Lx 25GbE rNDC OEM base

Sources

• Dell Mellanox ConnectX-4 Lx rNDC Specifications, checked 2026-10-27