Cisco QSFP-4SFP25G-CU5M Compatible 100G QSFP28 4 x 25G NRZ to 4 x 25G SFP28 NRZ Passive Copper Twinax Cable, 5m (16ft)

Product Highlights

• Compatible alternative to Cisco QSFP-4SFP25G-CU5M
• 100G connectivity at 100Gbps
• Interface configuration: QSFP28 to SFP28
• Fixed length and part number: 5m (16ft), QSFP-4SFP25G-CU5M
• Cable construction: Passive Twinax
• Conductor specification: 26AWG
• Maximum power consumption: ≤0.125W
• Minimum bend radius: 70mm

Specifications

Cisco OEM Reference

Cisco defines QSFP-4SFP25G-CUxM as a 100G QSFP to four 25G SFP passive copper breakout assembly. One end connects to a 100G QSFP port and the four branches connect to 25G interfaces on a switch or server. Correct channelization and lane mapping are essential for this HT compatible version as well.

Passive Copper Operation

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.

Length Selection and Installation Planning

The 5m (16ft) length gives QSFP-4SFP25G-CU5M more freedom for adjacent-rack and row-end deployments. Longer copper runs need particular attention to routing weight and bend control; the DAC specification and host support must still match the intended link.

Position Within the Length Range

QSFP-4SFP25G-CU5M is the longest of 8 verified length options in this family. Compared with QSFP-4SFP25G-CU3-5M at 3.5m (11ft), it provides 1.5m of additional reach for a longer vertical drop, a wider rack or an adjacent-cabinet route. Confirm that the complete path requires this length, because unused slack still needs supported, bend-safe storage.

Structured Pathways and Serviceability

Treat the direct-attach assembly as part of the permanent pathway plan even when the link is expected to be temporary. Follow the intended horizontal and vertical managers, maintain the specified bend radius and leave service access around both ports. A small, supported service allowance is preferable to excess slack concealed inside a rack or placed under cable-tie pressure. For this assembly, the listed conductor specification is 26AWG; the minimum bend radius is 70mm; the stated power consumption is ≤0.125W; the jacket material is PVC (OFNR).

Signal and Lane Configuration

The listed modulation format is QSFP28-4x 25G-NRZ SFP28-1x 25G-NRZ. 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.

Power and Thermal Planning

The rated power consumption is ≤0.125W. 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.

Cable Construction and Routing

This assembly uses 26AWG conductors, PVC (OFNR) jacket, minimum bend radius 70mm. 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.

Network and Protocol Considerations

The intended application is 100G to 4x 25G Ethernet, Data Centers. Listed interface and protocol references include IEEE 802.3, QSFP28 MSA, SFF-8665. Confirm that the host firmware and port configuration support the same operating mode.

Breakout Port Mapping

The QSFP28 to SFP28 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.

Ordering Information

Include the part number, fixed length, quantity and required pathway or rack grouping in the order information. The host model and firmware release are useful for change-controlled deployments. Different lengths should remain separate order lines so delivered labels and packing records agree with the pathway plan. Quantity and any labeling instructions should be attached specifically to QSFP-4SFP25G-CU5M.

Cisco Compatibility and Factory Testing

Verification covers the physical connectors, expected host identity and an operating link with available diagnostic indications. We distinguish this complete check from a simple continuity test. Platform model and software release can be reviewed in advance where the installation has strict documentation or change-control requirements. Both connectors are examined before the operating test, which includes link stability and diagnostic indications.

Shipping and Lead Time

Standard configurations normally ship within one to three working days, while production quantities are confirmed with the order. Delivery can be arranged by courier, air freight or sea freight, and goods may instead be handed to an appointed forwarder or shipped on the customer’s courier account.

Quality Assurance and Packaging

After connector inspection and link verification, the assembly is coiled without tight bends and packed with end protection. Labels can cross-reference the customer cable schedule, OEM part number and length. This supports both receiving checks and later moves, adds or changes. Standard protective packing is used by default, with project documentation arranged when requested.

Frequently Asked Questions