What is the difference between DAC and AOC Cables

Whether it’s a startup or a large enterprise, the importance of the data center to the IT infrastructure of companies of all sizes continues to grow. The growth of the data center is largely due to the proliferation of cybersecurity threats and the growing need for companies to have a robust infrastructure.DAC and AOC are two types of cables commonly used in today’s data centers. Understanding the differences between DAC and AOC cables helps IT managers make informed choices. This blog will cover the different DAC and AOC cable types, identify the right cables and select the right cables.

What is a DAC cable?

A direct-attached cable (DAC) is a copper cable with connectors on both ends.

Connectors usually have a latching mechanism or other device that prevents the connection from accidentally coming loose.DAC cables are designed to interconnect devices within a rack that are not normally mounted in the rack. These devices include network switches, servers, and storage devices.DAC cables are called direct-attach cables because they connect directly to the devices used for interconnection. They are also called “Twinax” cables because they consist of two pairs of twisted copper wires, commonly referred to as “Twinax” cables.


What are the DAC cable types?

There are two types of direct-connect cables: passive DACs and active DACs. passive DAC cables send data without signal conditioning. These cables are less expensive than active DAC cables. Active DAC cables contain electronics that amplify the signal. This signal is constantly compared to the data being sent and any changes are detected and corrected. Active DAC cables are much more expensive, but the improved signal helps with applications such as long distance and high resolution audio.

Depending on the data rate and connector type, DAC cables typically come in the following configurations: 10G SFP+ DAC cable, 25G SFP28 DAC cable, 40G QSFP+ DAC cable, 56G QSFP+ DAC cable, 100G QSFP28 DAC cable, 200G QSFP56 DAC cable, 400G QSFP-DD DAC Cables, 40G DAC Breakout Cables, 56G DAC Breakout Cables, 100G DAC Breakout Cables, 200G DAC Breakout Cables, 400G DAC Breakout Cables.

What is an AOC cable?
AOC cables are also known as active optical cables. They are multimode fiber optic cables with connectors on both ends and are typically used to connect the network equipment to the network termination device. It has a transmitter and a receiver built inside the cable, which converts electrical signals into light signals and transmits them into fiber optic cables.


What are the AOC cable types?
Based on the data rate and connector type, the AOC cable is typically available in the following configurations: 10G SFP+ AOC cable, 25G SFP28 AOC cable, 40G QSFP+ AOC cable, 56G QSFP+ AOC cable, 100G QSFP28 AOC cable, 200G QSFP56 AOC cable, 400G QSFP-DD AOC cable, 40G AOC Breakout Cables, 56G AOC Breakout Cables, 100G AOC Breakout Cables, 200G AOC Breakout Cables, 400G AOC Breakout Cables.

DAC vs. AOC Cables, What’s the Difference?
Choosing the right cables is critical to building a data center that runs well and keeps costs down. While the choice isn’t always straightforward, taking a few factors into account can make all the difference in determining what you use and how you use it.

Type Passive DAC Cable Active DAC Cable AOC Cable
Reach ≤7m ≤15m ≤100m
Cable Types Twinax copper cable Twinax copper cable Multimode OM3/OM4 Fiber Cable
Power Consumption Typical 0.1W Typical 0.5W Typical 1W
EMI High High Low
Bend Radius 24 AWG=38mm 30AWG=23 24  AWG=38mm  30AWG=23mm 3.0mm
Cable weight High High Low
Cable Size 4.2mm(30AWG) 4.2mm(30AWG)
6.0mm(24AWG) 6.0mm(24AWG) Typical 3.0mm
Application Top of Rack,
Adjacent racks
ToR,Adjacent racks ToR EoR MoR
Cost Low High Medium

How to Choose Between DAC & AOC cable?

Based on the above comparisons, you will recognize the difference between DAC cables and AOC cables. The average data center can benefit from the high performance network connectivity of DACs and AOCs, both of which are compact, all-in-one network connectivity solutions. But how do you choose between DAC and AOC cables?

Another consideration is cabling flexibility. dACs are made of thick copper cables whose thickness increases with bandwidth. 100G dACs are thicker than 10G dACs. aOC cables have a fixed thickness that is independent of bandwidth. aoc cables (3.0 mm in diameter) are typically twice as thick as typical copper wires (about 6.0 mm). AOCs are easier to install than DACs in tight spaces.

Widely used in high-performance computer systems, large commercial operations, and storage applications, DACs are ideal for short-haul transmission.DACs consume very little power, are extremely cost-effective, and offer excellent performance. They are ideal for connecting rack-mounted network servers and storage devices to top-of-rack switches.

Active fiber optic cables are ideal for long distance transmission as they can carry data up to 100 meters and feature ultra-high bandwidth, compactness, flexibility, resistance to electrical interference, and ease of installation.


For access-layer connectivity or scaling data center networks with a spine-leaf architecture, both DAC and AOC are available in the QSFP form factor. However, real-world testing reveals that AOC cables face challenges in comparison to traditional transceiver modules and fiber-optic cables. DAC, on the other hand, outperforms both alternatives.
In conclusion, the choice between DAC and AOC hinges on specific requirements, distances, and the adaptability needed for future network expansions.

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