Specifications
100G QSFP28 to 4×SFP28 Breakout Direct Attach Copper Cable Series
The QSFP28 to 4×SFP28 Breakout Direct Attach Copper (DAC) cable is a factory-terminated passive Twinax copper assembly designed for short-reach, high-speed Ethernet connections. It enables a single 100GbE QSFP28 port to be split into four independent 25GbE SFP28 ports, making it ideal for Top-of-Rack (ToR) switch-to-server connectivity in data centers, cloud computing and enterprise networks.
Passive breakout DAC cables provide a low-cost, low-latency and low-power alternative to using four individual optical transceivers and fiber patch cords. Each cable is factory tested and requires no separate optics or fiber installation.
| Parameter | Specification |
|---|---|
| Product Series | 100G QSFP28 to 4×SFP28 Breakout Passive DAC |
| Part Number | EN-Q28DACBO-3M |
| Form Factor | QSFP28 to 4×SFP28 |
| Ethernet Data Rate | 100GbE to 4×25GbE Breakout |
| Aggregate Data Rate | 100 Gb/s |
| Per-Lane Data Rate | 25.78125 Gb/s |
| Number of Lanes | 4 Transmit / 4 Receive |
| Signaling Format | NRZ |
| Cable Type | Passive Twinax Copper |
| Cable Length | 3 m |
| Cable Construction | Factory-terminated breakout copper cable |
| Conductor Gauge | Approximately 26–30 AWG |
| Wavelength | Not applicable |
| Fiber Type | Not applicable |
| Optical Transceivers Required | None |
| Power Supply | Powered from host interface (3.3 V) |
| Power Consumption | Passive (no active electronics) |
| Management Interface | EEPROM over I²C |
| Operating Temperature | 0°C to +70°C |
| Compliance | QSFP28 MSA, SFP28 MSA, SFF-8665, SFF-8402, IEEE 802.3bj, IEEE 802.3by, RoHS-6 |
| Applications | 100GbE to 4×25GbE Ethernet Breakout |
Features
- Passive QSFP28 to 4×SFP28 Twinax copper breakout cable
- Supports one 100GbE port split into four independent 25GbE ports
- Four electrical lanes operating at 25.78125 Gb/s each
- Factory-terminated cable assembly requiring no optical transceivers
- Low power consumption with no active signal conditioning
- Low latency for high-performance networking
- QSFP28 connector on one end and four SFP28 connectors on the other
- 3-meter cable length
- Ideal for Top-of-Rack switch-to-server deployments
- RoHS-6 compliant
Connectivity examples
Breakout DAC cables are commonly used to divide one 100GbE switch port into four separate 25GbE connections.
100G Switch to 100G Switch Direct Connectivity
100G Switch to 100G NIC Direct Connectivity
Breakout DAC Features and Advantages
Compared with using four separate optical transceivers and fiber patch cables, breakout DAC cables offer:
- Lower overall hardware cost
- Passive operation with virtually no cable power consumption
- Very low latency
- Simple plug-and-play installation
- No optical modules to purchase or maintain
- No fiber cleaning or polarity management
- Reduced cable count and improved rack organization
-
Ideal for high-density 100G-to-25G server connectivity
Applications
Deployment scenarios for this module
Data Center & Enterprise Networks
High-speed connectivity for leaf-spine architectures, server aggregation, and backbone upgrades supporting growing east-west traffic.
Telecom & Service Provider Transport
Robust optical connectivity for aggregation, metro, and long-haul transport across carrier and service provider networks.
Cloud, AI & Hyperscale Infrastructure
Reliable, low-latency links designed for high-performance computing, AI workloads, and scalable cloud environments.
Quality Certification
At E.C.I. NETWORKS, all our optical transceivers are CE, FCC, RoHS, and FDA laser compliant, meeting global standards for safety, environmental responsibility, and electromagnetic performance.
Key Certifications
Emissions and immunity compliance for IT and multimedia equipment.
Verified as unintentional radiators with SDoC available.
Safety-certified and laser-classified (Class 1).
U.S. laser safety regulations.
Free from hazardous substances and environmentally responsible.
Available on selected models per regional or customer needs.
Compliance Standards
These certifications ensure our transceivers are safe, interoperable, and built to meet the highest global compliance standards across data center, telecom, and enterprise environments.
Conflict-Free Sourcing
We comply with the SEC Conflict Minerals Rule, supporting ethical sourcing practices for minerals like tantalum, tin, tungsten, and gold.
Quality Certification
At E.C.I. NETWORKS, all our optical transceivers are CE, FCC, RoHS, and FDA laser compliant, meeting global standards for safety, environmental responsibility, and electromagnetic performance.
Key Certifications
Emissions and immunity compliance for IT and multimedia equipment.
Verified as unintentional radiators with SDoC available.
Safety-certified and laser-classified (Class 1).
U.S. laser safety regulations.
Free from hazardous substances and environmentally responsible.
Available on selected models per regional or customer needs.
Compliance Standards
These certifications ensure our transceivers are safe, interoperable, and built to meet the highest global compliance standards across data center, telecom, and enterprise environments.
Conflict-Free Sourcing
We comply with the SEC Conflict Minerals Rule, supporting ethical sourcing practices for minerals like tantalum, tin, tungsten, and gold.
Performance & Reliability
We ensure our optical transceivers deliver exceptional performance and long-term reliability through rigorous testing on industry-leading equipment.
Power & Wavelength Testing
We verify signal strength and wavelength stability to ensure seamless decoding and consistent transmission across the optical path.
Traffic Testing
All transceivers undergo bit error rate (BER) and packet loss testing to guarantee zero data loss and full compliance with Ethernet and Fiber Channel standards.
Optical Performance Validation
Our modules are evaluated for signal integrity, eye diagram clarity, and BER, ensuring stable, high-quality optical transmission in all operating conditions.
End Face Inspection
Each module's fiber interface is inspected and cleaned to eliminate contamination and physical defects - a critical step for optimal signal performance and long service life.
Warranty & Compatibility
DAC / AOC Cables: 5 Years
Zero Risk
Using our transceivers does not void the warranty of your network equipment. Global OEM policies and consumer protection laws (Magnuson-Moss Warranty Act) prevent manufacturers from denying support based solely on the use of third-party components.
Guaranteed Compatibility
Our modules are coded and tested for seamless operation across major platforms including Cisco, Arista, Juniper, HPE, Nvidia, Huawei, and more. This rigorous validation ensures plug-and-play reliability and full compliance with OEM specifications.
Technical Support & RMA
Have an issue? We provide full technical support and hassle-free RMA on all eligible transceivers. Our team is ready to help with any technical questions about compatibility or deployment. contact our technical support support@ecin.ca
Q&A
Commonly asked questions
No. Under the Magnuson-Moss Warranty Act and similar global consumer protection laws, OEMs cannot void your equipment warranty simply because you use a third-party transceiver. Your equipment warranty remains intact.
- AOC offers a plug-and-play optical solution (no separate optics + fiber needed)
- Combines ease of deployment + longer reach + better density
The QSFP28 Breakout DAC series consists of passive QSFP28-to-4×SFP28 Direct Attach Copper (DAC) cables designed for 100GbE breakout applications. Each cable connects one 100GbE QSFP28 port to four independent 25GbE SFP28 ports, providing an aggregate bandwidth of 100 Gb/s (4 × 25.78125 Gb/s). The EN-Q28DACBO-3M is a fixed-length 3-meter passive Twinax cable intended for short-reach, high-speed connections within data center racks.
No need for:
- Fiber patching
- Optics matching (SR4, DR4, etc.)
Factory-terminated and tested
QSFP28 Breakout DAC cables are ideal for high-density data center and enterprise network deployments where a single 100GbE switch port needs to connect to four separate 25GbE devices, including:
- 100G switch to four 25G server or NIC connections
- 100G switch to four 25G switch ports
- Top-of-Rack (ToR) server deployments
- High-performance computing (HPC) environments
- Cloud and enterprise data centers
- Same-rack and adjacent-rack connections
Their passive Twinax copper design delivers low latency, low power consumption, and a cost-effective alternative to using four optical transceivers and fiber patch cords for short-distance 100G-to-25G breakout applications. While breakout DAC cables are less flexible and have a shorter reach than Active Optical Cables (AOCs), they provide an economical solution wherever passive copper connectivity is suitable.
Available for:
- QSFP28 / QSFP-DD / OSFP
- Multi-vendor environments (Cisco, Arista, Nvidia, SONiC)
Yes. We offer full 5Y support, RMA service, and warranty coverage on all modules.
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Resources
Downloads and documentation