QSFP+ Direct Attach Copper(DAC) Cable Assemblies are designed for Infiniband 10 Gigabit Ethernet and 40 Gigabit Ethernet applications. These cable assemblies provide four channels of data in one pluggable interface. Each channel is capable of transferring data at 10Gbps and supports a total of 40 Gbps data rate. And meet all IBTA, QSFP MSA and SFF-8436 ,Infiniband QDR specification requirements. Compare with fiber optical cable assemblies, QSFP+ direct copper cable provide a cost-effective solution in data centre short reach interconnects applications.
The 1m 40G QSFP+ to QSFP+ Direct Attach Copper Cable (DAC) is an ultra-short reach passive Twinax cable designed for 40Gbps Ethernet interconnections within a single rack. This 1-meter cable provides a near-zero latency path and zero power consumption, making it the most energy-efficient and cost-effective alternative to 40G transceivers for Top-of-Rack (ToR) switch-to-switch or switch-to-server stacking.
At the 1-meter length, cable flexibility (AWG) and signal integrity at high frequencies are the primary differentiators.
| Feature | 40G QSFP+ Passive DAC (1m) | 40G QSFP+ AOC (1m) |
| Transmission Media | 30AWG Twinax Copper | 850nm Multimode Fiber |
| Power Consumption | 0W (Passive) | ~1.5W per end |
| Latency | Lowest (No O-E Conversion) | Micro-delays (Signal Conversion) |
| Durability | High (Robust Copper) | Moderate (Fragile Fiber) |
| Bending Radius | 25mm - 30mm | 30mm |
| MTBF (Reliability) | Superior (No active lasers) | High |
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 copper cable are copper wire so there are no delays in switching copper signals to optical and then back to copper. Direct attach copper cables have the lowest latency of all short-reach cables (<8ft /3m). For services such as financial trading, edge computing, AI, AR/VR gaming, enterprise video conferencing, any reduction in latency is an advantage. DAC cables offer low-latency connectivity, ensuring that data travels quickly and efficiently between interconnected devices.
lHot-plug swappable
l3X Port Density over SFP / SFP+
lOptimized NEXT & Return Loss
lLow cost and low power solution compared to fiber optical cable
lCompliant with QSFP+ MSA and SFF-8436
lCompliant with IEEE 802.3ba/ Infiniband QDR specifications
lEnhanced EMI/EMC performance
lSupports serial ID functionality thru EEPROM
lPassive cable assembly supports distances up to 7 meters
l30AWG to 24AWG cable sizes available
lRoHS compliant and Halogen-Free option available
lSwitches / Routers / HBAs/SAN, NIC cards
lServer & Storage Devices
lData Center Networking
lHigh Performance Compute
lFiber Channel
lInfiniBand QDR/DDR
l10Gbs/40Gbs Ethernet
The 1m 40G DAC is the go-to solution for Switch Stacking, HCI (Hyper-Converged Infrastructure) nodes, and High-Performance Computing (HPC) clusters. It is designed to withstand the tight bends required in 1U and 2U rack deployments. Explore our
This DAC Cable feature with 40G QSFP fiber transceiver, which could be compatible with different switches brands, likes Cisco, Juniper, H3C, Huawei, Alcatel, Allied Telesis, Zyxel, Brocade, Mikrotik, Extreme, Blade, D-linnk Netgear, Finisar, ZTE, Linksys, SMC, Ruijie, Avaya, 3com, Enterasys, Redeback, Planet etc.
For 1-meter connections, many people over-engineer by using AOCs. From an application perspective, a 1m DAC is actually more reliable because it has fewer active components to fail. At UnitekFiber, we focus on the EEPROM handshake—ensuring that when you plug this 1m cable into a Cisco Nexus and an Arista switch, they recognize each other instantly without CLI workarounds.
Every rack environment presents its own set of hurdles, from port-density cooling issues to multi-vendor compatibility headaches. At UnitekFiber, we don't just sell cables; we help you design a stable physical layer. If you are unsure whether 30AWG or 26AWG is better for your airflow, or if you need a custom-coded "dual-vendor" cable for a mixed-brand setup, our engineering team is ready to assist.
Let us help you eliminate the guesswork in your next 40G deployment. Consult our experts:
A 1m DAC is roughly 1/5th the cost of two transceivers and a fiber patch cord. It also consumes zero power and is much more durable for frequent re-patching.
The transmission medium of DAC is copper cable.
High-speed cables are mainly used for transmission in data center cabinets. Because high-speed cables do not use expensive optical components and optical fibers as components, the transmission distance is short and the price is low. It is very suitable for the connection of servers and switches in the cabinet.
Yes, the 40G AOC/DAC cable has a QSFP+ to 4*SFP+ branch cable. Using this specification cable, the 40G port and the 10G port can be interconnected.
The longest transmission distance of copper cable DAC is 7M.
We offer multi-coding services. We can program the cable to be compatible with Cisco, Arista, Mellanox, Dell, and 100+ other brands to ensure "Plug-and-Play" operation.
Technically, no. This is a QSFP+ to QSFP+ cable. If you need to connect a 40G port to a 10G port, you would require a Breakout DAC.
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.
On time delivery and always has great customer service!
This DAC cable has greatly improved our network efficiency.
I'm really impressed with this 40G QSFP to QSFP DAC cable. It's incredibly easy to install, and the hot - plug swappable feature is super convenient.
This DAC cable is compatible with ZTE devices in our data center, from servers to storage units.
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