In data centers, DAC (Direct Attach Copper) and AOC (Active Optical Cable) are two commonly used high-speed connectivity cables. They may look similar in appearance but differ significantly in functionality and application scenarios. Understanding the differences between them helps make more appropriate choices when building or upgrading data centers.
What is a DAC Cable?
A DAC cable is a copper-based cable with standard connectors (such as SFP+, QSFP+) at both ends. It transmits electrical signals directly without the need for additional signal conversion modules.
Its characteristics are obvious: the transmission distance is short - passive DACs typically reach only 3-7 meters, and active DACs max out at 15 meters. However, it has low cost and low power consumption - passive ones consume almost no power, and active ones operate within 1W. Nevertheless, the copper material makes it susceptible to electromagnetic interference, making it more suitable for short-distance scenarios with simple electromagnetic environments.
In data centers, DACs are commonly used for device connections within the same rack (e.g., between servers and switches) or short-distance interconnections between adjacent racks (within 10 meters). They enable high-speed transmission from 10Gbps to 100Gbps at a relatively low cost.
What is an AOC Cable?
An AOC cable features multi-mode optical fiber as its core, with integrated optical transceivers at both ends. During operation, electrical signals are first converted to optical signals for transmission through the fiber, then converted back to electrical signals at the destination.
Its advantage lies in long-distance transmission: using OM3 fiber can reach 100 meters, and some products even exceed 300 meters. Additionally, optical fiber is immune to electromagnetic interference, ensuring strong signal stability. However, it has higher costs and power consumption (around 1-2W) due to the need for optical transceivers for signal conversion.
AOCs are suitable for long-distance connections in data centers, such as interconnections between cross-rack or cross-floor devices, or scenarios with extremely high requirements for signal quality like high-performance computing and financial transactions. They support high-speed transmission from 10Gbps to 400Gbps.
Core Differences and Selection Recommendations
The core differences can be summarized as: DAC uses copper to transmit electrical signals, offering short distance, low cost, and susceptibility to interference; AOC uses optical fiber to transmit optical signals, providing long distance, anti-interference capability, and higher cost.
When making a selection, first consider the distance: prioritize DAC for distances within 10 meters, as it is cost-effective and sufficient; choose AOC for distances exceeding 10 meters to ensure stable transmission. Additionally, AOC is more reliable in complex electromagnetic environments or scenarios requiring long-term high bandwidth; DAC is more economical for short-distance connections with limited budgets.
In conclusion, DAC and AOC each have their strengths. Data centers usually use them in combination according to specific connection requirements to ensure efficiency while controlling costs.
Boasting over 100 product testing devices, every DAC and AOC cable from
Fiberwdm meets stringent standards. Their dedicated technical support team addresses all product - related issues, from operation to technical challenges. Whether you need a cost - effective short - range DAC or a high - performance long - distance AOC, Fiberwdm delivers tailored solutions to enhance your data center's stability and efficiency.
