What Is the Difference Between SFP Transceivers and Direct Attach Cables (DAC)?

Equal Optics

Streamlined connectivity for your industry relies on reliable transceivers. With the advent of 10G Ethernet networks, it’s more important than ever to choose the most efficient network transceivers. Explore the differences between SFP transceivers and Direct Attach Cable (DAC) to see the advantages and applications of each in your network. Discover how Equal Optics can deliver the OEM transceivers you need to improve your network and enhance its efficiency.

What Are SFP Transceivers?

Small form-factor pluggable transceivers are designed to deliver information between switches and other essential components within a network. It can be used to connect fiber optic or copper and offers hot swappable capabilities. As a compact, versatile transceiver, SFP is a popular option for many networking solutions that require rapid, long-distance data transfer.

These transceivers come in wavelength options between 850 nm and 1550 nm. If you’re using them in fiber optic connections, then you can choose between simplex and duplex, as well as between single mode and multimode fiber. While there isn’t an internationally recognized standard for SFP modules, this type of transceiver is typically compatible between brands.

Benefits of an SFP Transceiver

Consider using an SFP transceiver for your networking application, rather than DAC or other alternatives, to enjoy these and other benefits:

  • Hot swapability: You can replace or remove an SFP transceiver without requiring the device to be rebooted or causing other disruptions.
  • High transmission range: SFP transceivers enjoy a competitive transmission range, typically about 120 km.
  • Fast transfer rate: Transfer data at rapid rates, typically between 10 Gbps and 25 Gbps, with lower latency than other transceiver options.

Applications of SFP Transceivers

Thanks to its compatibility with a broad range of fiber optic applications, from Ethernet to STM-X, an SFP transceiver is a flexible option. Use an SFP transceiver to create a bridge between network switches, particularly with copper modules. SFP technology is a great way to make fast connections with a more streamlined setup. Fiber optic applications are extensive and include both long-range and high-range cabling options.

What Is the Difference Between SFP Transceivers and Direct Attach Cable (DAC)? | Equal Optics

What Are Direct Attach Cables (DAC)?

Direct attached cables have transceiver housings on both ends of the copper cable, typically made from twinax cable. In some cases, a DAC cable also has a transition to connect a single QSFP module termination with four SFP modules. DACs are capable of being used in both active and passive variants.

Benefits of a Direct Attach Cable (DAC)

Explore the key benefits of using this type of transceiver to replace an existing transceiver or to implement a new networking solution:

  • Affordable connections: Compared with SFP transceivers, using DAC cable to connect routers is a more cost-effective solution.
  • Reduced heat dissipation: In general, DACs tend to dissipate heat better than other connectivity options.
  • Lower power consumption: Using DAC to connect switches and other devices typically uses less power than alternative transceivers.

While Direct Attach Cables (DAC) offer several distinct benefits, it’s important to note that they cannot be used to connect to legacy equipment.

Applications of a Direct Attach Cable (DAC)

Similar to an SFP transceiver, Direct Attach Cables (DAC) are used to connect switches and other components in a network. The cabling is directly connected to transceiver housings and uses copper wiring to transfer information instead of fiber optic cables. Choose DAC solutions for top-of-the-rack data center applications. The budget-friendly, short-reach nature of these transceivers works well in a top-of-the-rack situation, which doesn’t require an extensive connection length. This transceiver option also supports 4x10G and 4x25G applications.

How Do You Compare SFP and Direct Attach Cables (DAC)?

The best option for your connectivity needs depends on the particular application. For example, short-distance connections within data centers are generally achieved using DACs. On the other hand, SFP transceivers may be better suited to long-distance applications that require a slim, flexible cable. For a more in-depth comparison, review the following features to see how the two transceiver options differ.

Short-Distance Transmission

For distances of 15 meters or less, using an SFP transceiver may not be necessary. These short-term connections can be achieved with DAC solutions without the additional cost of SFP technology. Both options can achieve a short-distance connection, but DAC offers a more cost-effective solution for these applications.

Long-Distance Transmission

Longer transmissions are where DAC technology falls short. Distances over 15 meters fall beyond the reach of Direct Attach Cables, so you’ll likely need to use an SFP transceiver for these applications.


SFP transceivers cost more than DAC alternatives. While this technology is worth the investment in many situations, it may not be in others. Consider the distance and latency requirements of your application to see if you can choose the more budget-friendly DAC option or if you need to invest in the low latency, long-distance SFP technology.

Legacy Connectivity

Despite the advancements of DAC cables, they can’t be used to connect legacy equipment. If you’re using older equipment, you may not have the option of Direct Attach Cables unless you update that equipment as well.


A crucial factor in data centers and other applications, latency is the amount of time it takes for data packets to be transmitted from origination to destination. SFP transceivers offer very low latency compared with DAC cables. While a few nanoseconds of difference may not be necessary for some applications, it’s a major distinction in applications that require very low latency.

Power Usage

Both transceiver options are relatively efficient when it comes to power consumption. DAC, however, manages to deliver data at slightly lower levels. These efficiencies can add up, so if you’re looking for a short-distance connection with low power consumption, consider using DAC technology.


DAC cabling using copper wiring, which is thicker and less flexible than SFP cabling. Consider using SFP for your connections if you’re working in a confined space or need additional flexibility in the connection.

Learn More About DAC and SFP Transceivers

Whether you’re considering SFP transceivers or DAC alternatives, turn to Equal Optics for a broad selection of industry-leading components. Contact us today to learn more about the benefits of both SFP and DAC options to power your network and make efficient connections.



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