Cisco QSFP-4SFP25G-CU3-5M Compatible 100G QSFP28 4 x 25G NRZ to 4 x 25G SFP28 NRZ Passive Copper Breakout Cable, 3.5m (11ft)

Product Highlights

• Compatible alternative to Cisco QSFP-4SFP25G-CU3-5M
• 100G connectivity at 100Gbps
• Interface configuration: QSFP28 to SFP28
• Fixed length and part number: 3.5m (11ft), QSFP-4SFP25G-CU3-5M
• 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.

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.

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 3.5m (11ft) length gives QSFP-4SFP25G-CU3-5M 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-CU3-5M occupies the middle of this family between QSFP-4SFP25G-CU3M at 3m (10ft) and QSFP-4SFP25G-CU5M at 5m (16ft). It adds 0.5m over the shorter option for extra routing clearance, while the next longer version adds another 1.5m. Measure the managed path and choose this version when its reach is sufficient without creating the slack associated with the longer assembly.

Data-Center Design and Airflow

Select the assembly by both reach and rack layout. A direct connection removes separate module-and-patch-cord interfaces, but it still needs a bend-safe pathway and clear connector access. Keep cable bundles from blocking front-panel airflow, account for the listed interface power where applicable and choose a length that supports maintenance without leaving an unmanaged coil. 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.

Quality Assurance and Packaging

Each cable receives connector inspection and a functional link check before it is coiled with bend-safe slack and packed. Protective materials shield the connector housings during transport. Rack or project labels are available to keep length, part number and installation destination aligned. Neutral packaging and customer-specific packing documentation are available on request.

Ordering Information

Provide the OEM reference, HT part number, fixed length and quantity, together with the intended host interfaces. Rack-based quantities and packaging instructions can be included for larger deployments. Other lengths are separate products and should be entered on their own order lines. Keep QSFP-4SFP25G-CU3-5M associated with 3.5m (11ft) throughout the order and receiving record.

Cisco Compatibility and Factory Testing

Compatibility confirmation combines host identification with actual link establishment and diagnostic checks. The assembly is prepared for the stated OEM reference rather than selected only by connector shape. For a new data-center deployment, the equipment model, port mode and software release provide the most useful basis for a pre-order review. Where supported by the host, link stability and diagnostic indications are reviewed together with the established link.

Frequently Asked Questions

Shipping and Lead Time

Standard configurations normally ship within one to three working days, while production quantities are confirmed with the order. International express, air cargo and sea freight can be selected according to destination and carton volume; customer courier accounts and nominated forwarders are also accepted.