QSFP+ DAC cable consists of two QSFP fiber transceiver modules that are directly connected to the DAC cable. 40G QSFP+ direct attach copper cables are designed for 40 Gigabit Ethernet applications, using in the short distance connections within or between adjacent racks in the data center. 40G DAC cables provide a QSFP+ to QSFP+ copper direct attach solution. QSFP+ direct attach copper cables provide a cost-effective solution for short-haul interconnect applications in data centers. DAC cables are easy to install, fast, and cost-effective for short distance transmission.
The 40G QSFP+ Direct Attach Copper Cable (DAC) is a high-performance passive Twinax cable designed for short-distance 40G Ethernet links (up to 7m). It features two QSFP+ connectors directly soldered to a shielded copper cable, offering a zero-power consumption and near-zero latency solution for Top-of-Rack (ToR) switch-to-server or switch-to-switch connections. It is the most cost-effective alternative to optical transceivers for data center cabling.
The direct attach copper cable is commonly using in the short distance of data transmission, so the length of the DAC cable are usually 1m/2m/3m/5m/7m. For the short distance, 40G DAC cable is widely used for establishing connections within the same rack or between adjacent racks in data centers. This intra-rack and inter-rack connectivity is essential for linking networking equipment, servers, and storage devices, creating a cohesive and high-performance infrastructure within the data center environment.
DAC cable is to provide cost-effective networking solutions for short distance connections. As an alternative to optical transceivers and fiber optic cabling, direct attach copper cable offer comparable performance at a lower cost, making them an economical choice for high-speed data transmission in limited network space. The internal material of the high-speed DAC cables is copper core, which is both energy efficient and environmentally friendly as it provides natural heat dissipation. The active optic cables typically consume around 440mW, but the direct attached copper cable do not require a power source, it could save on the on electricity costs.
If you are looking for a potential DAC cable solution to solve network latency, utility costs or density issues, let UnitekFiber help. We are committed to providing high-quality DAC cable that undergo stringent testing procedures. Our meticulous approach encompasses every step, from careful material selection to rigorous performance evaluations. By adhering to these rigorous standards, our DAC cable are designed to deliver reliable and high-performance data transmission in even the most demanding network environments. With the incorporation of top-quality components and our unwavering commitment to stringent testing processes, the DAC cable has become the trusted choice for network professionals who seek unparalleled quality and performance.
In 40G networking, DAC is the undisputed king of cost-efficiency for distances under 5 meters.
| Feature | 40G QSFP+ Passive DAC | 40G QSFP+ AOC (Optical) |
| Transmission Media | Twinax Copper (30AWG-26AWG) | Multimode Fiber (OM3) |
| Max Reach | 7 Meters | Up to 100 Meters |
| Power Consumption | 0.1W (Negligible) | ~1.5W per end |
| Latency | Lowest (No O-E Conversion) | Micro-delays due to conversion |
| Cost | $ (Most Economical) | $$$ (Higher Investment) |
| Standard Compliance | SFF-8436 / IEEE 802.3ba | SFF-8436 |
I often advise clients: if your link is under 3 meters, there is absolutely no reason to pay for optics. Our 40G DACs are programmed with industry-standard EEPROM signatures, meaning they 'handshake' instantly with Cisco Nexus or Arista switches. No 'unsupported transceiver' warnings—just instant 40G throughput. — UnitekFiber
The 40G QSFP+ DAC is the "hidden hero" of Storage Area Networks (SAN) and HCI (Hyper-Converged Infrastructure). It is perfectly suited for high-throughput backup tasks and low-latency database clustering within the same or adjacent racks.
Discover our
Stop overspending on short-range optics. UnitekFiber offers premium, factory-tested 40G DACs in lengths of 0.5m to 7m. High-volume stock is available for immediate global deployment.
Get Your Quote Now:
Passive DACs (like this one) have no signal amplification and are best for distances under 7m. Active DACs include a chip to boost the signal, allowing for slightly longer reaches over thinner copper, though they are less common than AOCs for 40G.
You would need a 40G QSFP+ to 4x10G SFP+ Breakout DAC for that specific application. This standard DAC is for 40G-to-40G straight connections only.
Yes. While they don't produce heat, 40G DACs (especially 26AWG versions) are thicker than fiber. Proper cable management is required to ensure they don't block the cold-aisle intake or hot-aisle exhaust of your switches.
DAC cables are made from shielded Twinax copper coaxial and are factory equipped with modules on either end connected to fixed ports. The modules cannot be removed from the cable. Therefore, all DAC cables are produced at a fixed length.
Direct Attached Cables, or DACs, are copper cable assemblies made from twinax cable, terminated with transceiver housings on each end. DACs are available in passive or for active variants. Passive DACs are typically 7m in length or shorter and use less than 0.15W of power.
UnitekFiber's DAC cables includes passive direct-attach cables with speeds ranging from 10 Gbps to 400 Gbps, typically used for short-distance connections in enterprise and data centers or network equipment.
Direct Attach over Copper (DAC) cables have a minimum bend radius of typically 4x the diameter of the cable (approximately a 1" bend radius).
Before shipping, we have professional QC,and we will test the item strictly.
This product do a well work on the data center, absolutely save the space, save the installation time and could be manage the cable better than before. Highly recommended.
This DAC cable has greatly improved our network efficiency.
Our data center was in dire need of a more efficient cabling solution, and the direct attach copper cable delivered exactly that.
Seems to be well constructed , works perfectly as expected.
The DAC cable have simplified our cable management and reduced the time required for installation and maintenance.
+86-755-21034367
