The differences between Direct Attach Cables and Active Optical Cables

If you are wondering what are the differences between Direct Attach Cables (DAC) and Active Optical Cables (AOC), this article is for you.

Direct Attach Cables (DAC)

Direct Attached Cables are a very common method used for very short-range distances because of the their low-cost. Indeed, they are the cheapest solution to connect network equipment. DAC are the perfect solution to linked switches, servers and storage inside racks. In addition, it is a one part product instead of the usually three part solution (two transceivers and a cable), which reduces the problems associated with dirty connectors.

Direct Attached Cables consume less power compared to Active Optical Cables (AOC) but they are heavier and vulnerable to the effects of electromagnetic interference (EMI).

There are two types of DAC, the passive copper cable for distance from 0 to 5 meters and active copper cable for distance from 5 to 15 meters


     40G QSFP+ to 40G QSFP+ DAC

100G QSFP28 to 4 x 25G SFP28 DAC

           100G QSFP28 to 4 x 25G SFP28 DAC

Active Optical Cables (AOC)

Active Optical Cables are comparable to using transceivers and separated cables. AOC are mostly used to connect switches, servers and storage between different racks inside a data center for example.

They can reach longer distance than Direct Attached Cables, up to 100 meters depending on the data rate and the type of fiber cable used. They are lighter and smaller than DAC, but they are more expensive, which is one of their main drawback. Unlike DAC, AOC are immune to EMI.

100G QSFP28 to 100G QSFP28 AOC

           100G QSFP28 to 100G QSFP28 AOC

40G QSFP+ to 4 x 10G SFP AOC

40G QSFP+ to 4 x 10G SFP AOC

Of course, if you need to reach longer distance you can always choose to use optical transceivers. The distance reached depends on the data rate but it can reach up to 120km for 1G SFP or 40km for 100G QSFP28 transceivers. To know more about optical transceivers you can check our Complete Guides.

Direct Attach Cables Products

10G SFP+ DAC 10G SFP+ to SFP+ DAC OPSFPP-T-xx-P xx= 0,5 to 7 meters
40G QSFP+ DAC 40G QSFP+ to QSFP+ DAC OPQSFP-T-xx-P xx= 0,5 to 7 meters
40G QSFP+ to 4 SFP+ DAC OPQSFP-T-xx-P/SFPP/4 xx= 0,5 to 7 meters
25G SFP28 DAC 25G SFP28 to SFP28 DAC OPSF28-T-X5-PE xx= 0,5 to 5 meters
100G QSFP28 DAC 100G QSFP28 to QSFP28 DAC OPQS28-T-XX-PE  xx= 0,5 to 5 meters
100G QSFP28 to 4 SFP28 DAC OPQS28-T-XX-P/SF28/4 xx= 0,5 to 5 meters
400G QSFP-DD DAC 400G QSFP-DD to QSFP-DD DAC OPQSDD-T-X5-PEE xx= 0,5 to 3 meters

For DAC products, the length and the gauge size can be customized upon request.

Active Optical Cables Products

10G SFP+ AOC 10G SFP+ to SFP+ AOC OPSFPP-F-xx-AK xx= 1 to 100 meters
40G QSFP+ AOC 40G QSFP+ to QSFP+ AOC OPQSFP-F-xx-AKA xx= 1 to 100 meters
40G QSFP+ to 4 SFP+ AOC OPQSFP-F-xx-A/SFPP/4 xx= 1 to 100 meters
25G SFP28 AOC SFP28 to SFP28 AOC OPSF28-F-xx-AKT xx= 1 to 100 meters
100G QSFP28 AOC 100G QSFP28 to QSFP28 AOC OPQS28-F-XX-AK xx= 1 to 100 meters
100G QSFP28 to 4 SFP28 AOC OPQS28-F-xx-A/SF28/4 xx= 1 to 100 meters
400G QSFP-DD AOC 400G QSFP-DD to QSFP-DD AOC OPQSDD-F-xx-A xx= 1 to 100 meters

For AOC products, the length and type of fiber cable (single mode, multimode, OM3, OM4,..) can be customized upon request.

For information, Optech products are compatible with major switches and servers brands on the market. You can check all the compatible lists here.

About Optech

Optech Technology Co. Ltd was founded in 2001 in Taipei, Taiwan. The company was created with a sole purpose, to provide a wide and high quality portfolio of optical products to a very demanding and fast evolving market.

To respond to the permanent increase of IP traffic, Optech portfolio is constantly growing. Since the beginning, the company has always been up to date with the latest innovations on the market. Today, we are proud to deliver a large selection of 25G SFP28, 40G QSFP+, 100G QSFP28 and 400G QSFP-DD optical transceivers and cables.

Optech has a large portfolio of products which include optical transceiversdirect attach cablesactive optical cablesloopback transceiversmedia converters and fiber patch cords.

Through its large selection of optical products, that have a range of data speed from 155 Mbps to 400 Gbps and reach distances up to 120km, Optech products are suitable for various industries such as telecom, data centers as well as public and private networks.

Optech also has a strong experience as an OEM supplier. We put our expertise and knowledge at the service of your brand.

To ensure the quality and the compatibility of our products, every product is carefully tested before delivery to our customers. In addition, Optech obtained several certifications such as UL, TUV Rheinland, ISO9001 and ISO14001 certification. All our optical transceivers are MSA and RoHS compliant.

At Optech, we value each and every customer. We know every demand is unique. For this reason, our team of experts is glad to answer all our customers’ specific demands.

Just like data, Optech has no boundaries and will optimize your network all over the world.

For more information you can visit or contact us at