Arista Networks CAB-D-8S-400G-0.5M Compatible 400G QSFP-DD 8 x 50G PAM4 to 8 x 50G SFP56 50G PAM4 Passive Copper Breakout Cable, 0.5m (2ft)

This HT cable matches the CAB-D-8S-400G-0.5M requirement for Arista Networks equipment. The 0.5m (2ft) assembly supports 400G operation and provides a factory-terminated passive copper link without separate optical modules or patch cords; its complete electrical and mechanical details are listed below.

OEM Part Number: CAB-D-8S-400G-0.5MHT Part Number: CAB-D-8S-400G-0.5M

Product Highlights

• Compatible alternative to Arista Networks CAB-D-8S-400G-0.5M
• 400G connectivity at 400Gbps
• Interface configuration: QSFP-DD to 8x SFP56
• Fixed length and part number: 0.5m (2ft), CAB-D-8S-400G-0.5M
• Cable construction: Passive Breakout DAC
• Conductor specification: 30AWG
• Maximum power consumption: 0.1W (QSFP-DD End)0.1W (SFP56 Per End)
• Minimum bend radius: 33.5mm

The listed modulation format is QSFP-DD-8x 50G-PAM4SFP56-50G-PAM4. Both host interfaces must be configured for the same aggregate rate and lane arrangement. A connector that fits mechanically does not by itself guarantee that the remote port supports this encoding or breakout mode.

A passive DAC has no separate optical conversion stage. Its low-power, low-latency operation is useful for short equipment links, but the assembly must remain within the length and signaling mode accepted by both hosts.

The 0.5m (2ft) length is suited to closely aligned ports where excessive slack would obstruct airflow or complicate dressing. Measure the actual port-to-port path before choosing CAB-D-8S-400G-0.5M; even a short assembly must retain the specified bend radius and should never be pulled tight behind the equipment.

CAB-D-8S-400G-0.5M is the shortest of 6 verified length options in this family. It is the preferred choice when the port positions are close and cable slack must be kept to a minimum. The next option is CAB-D-8S-400G-1M at 1m (3ft), adding 0.5m for a less direct routing path; selecting it unnecessarily would leave more cable to dress.

The rated power consumption is 0.1W (QSFP-DD End)0.1W (SFP56 Per End). Include this load in the host-port power and thermal budget, especially in densely populated switches. Maintain front-panel clearance and do not bundle the cable so tightly that it obstructs airflow around the connectors.

This assembly uses 30AWG conductors, PVC (OFNR) jacket, minimum bend radius 33.5mm. These mechanical characteristics affect how the cable should be dressed behind the equipment. Avoid sharp edges, excessive ties and repeated tight bends close to the connector boots.

The intended application is determined by the host interface and protocol support. Listed interface and protocol references include QSFP-DD MSA, SFF-8432, IEEE 802.3bs-400GAUI-8, IEEE802.3cd-50GAUI-1, CMIS 4.0, SFF-8472. Confirm that the host firmware and port configuration support the same operating mode.

The QSFP-DD to 8x SFP56 configuration divides the high-speed interface into multiple lower-speed connections. Verify the upstream lane assignment, downstream port speeds and breakout setting on the host before connecting the assembly. Each branch must attach to the correct remote interface.

The assembly is configured for equipment that recognizes CAB-D-8S-400G-0.5M. Before shipment, we inspect both connectors and verify identification, link establishment and electrical continuity, link stability and diagnostic readouts. Host hardware and firmware revisions can affect third-party cable acceptance, so customers can provide the equipment model and software release for a pre-order compatibility review.

This product is ordered as CAB-D-8S-400G-0.5M in 0.5m (2ft). Include the equipment model and software release if you would like a pre-order compatibility review. Other lengths use different part numbers and should not be substituted into the same order line.

Quality control includes connector appearance, cable identification and functional verification. Packing materials are selected to keep the connector housings and cable boots from taking impact during transport, and the coil is not compressed into an undersized bundle. Volume orders can include customer-specific labels and packing documentation.

Standard configurations normally ship within one to three working days. Worldwide courier, air freight and sea freight options are available, and shipments can also be sent on your own courier account or delivered to an appointed forwarder.