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Things Should Be Considered When Buying Direct Attach Copper Cables

Things Should Be Considered When Buying Direct Attach Copper Cables

SFP+ DACDirect attach copper cables, namely DAC cables, are a form of optical transceiver assemblies used to connect switches to routers and/or servers. They are becoming increasingly popular in the network industry, mainly because the price difference is so large when compared with regular optics. There are various versions of DACs with different specifications on the market today which make us in difficult choices. So, what should be considered when we buy DAC cables? Just keep reading, you may find the answer in this post.

Choose Passive or Active?

A passive DAC cable, such as the 10GbE SFP+ DAC, is effectively viewed as a transparent cable to the switch and requires little to no direct power to operate. A passive cable therefore passes the signal through it without any modification or processing such as amplification or equalization. Whereas active DAC cable contains electrical components in the connectors that boost signal levels that make data available to transmit for longer distance. In general, active DAC cables are slightly more expensive than passive DAC cables. How to determine which type should be used? In addition to the consideration of cost and transmission distance, the most reliable method is to check the compatible matrix of your switch. Because some of the switch may not support the passive version, like Brocade VDX.

Choose the Right Connector

DAC cable terminated with SFP+ connectors is commonly used in 10GbE networks. However, there are many other connector options for DAC cables which meet the interconnection demands of higher speed networks. Thus, choosing the right connector according to your network requirement is very important. In general, you could choose the SFP+ for 10GbE, QSFP+ for 40GbE, SFP28 for 25GbE and QSFP28 for 100GbE. In addition, breakout DACs like QSFP+ to 4x SFP+ DAC is an ideal choice for 10G to 40G migration.

AWG Is Also an Important Factor

AWG is another important factor of DAC cables. General specifications like 24AWG, 28AWG and 30AWG are available in the market. Always remember a rule when choosing the AWG—the longer the distance, the higher the AWG rating should be.

Choose the Enough Length

The maximum cable length differs from passive and active DAC cables. Generally, passive cable supports 5 meters or shorter lengths. Whereas active cable can support more than 5 meters (up to 15 meters). Thus, when the distance between connection points is less than 5 meters, passive DAC cable is recommended to use but ensure that your switch can support the passive cable (refer to the first guide). When the distance exceeds 5 meters, it is highly recommended to use active DAC cables to ensure the signal is transferred all the way through. The cost may be a bit higher, but the signal is improved and gives peace of mind by creating a trustworthy connection.

DAC cables are a low-cost alternative to traditional fiber and twisted-pair copper cabling in top-of-rack and middle-of-row. When buying a DACs, parameters such as passive or active, cable connector, AWG, length and so on should be properly selected. This post is a simple buying guide for reference. If you want to purchase high-quality and cost-effective DAC cables, it is highly recommended to visit FS.COM or contact for more details.

10Gigabit Ethernet Transceiver Options for Server Connectivity

10Gigabit Ethernet Transceiver Options for Server Connectivity

10 Gigabit Ethernet is becoming increasingly common, physics of the cabling plant including latency, distance, power consumption, technology availability as well as cost should be carefully considered by users when designing for 10 Gigabit Ethernet cabling infrastructure. This post introduced several 10Gigabit Ethernet transceivers and cables for server connectivity.

10 Gigabit Ethernet Over Copper

Many IT departments still use copper cabling for switch-to-switch or switch-to-server connections in 10 Gigabit Ethernet due to the low cost of copper cables. Now, two major copper cabling technologies are available for 10 Gigabit Ethernet over copper.

Connector (Media) Cable Max. Distance Protocol
SFP+ CU copper Twinax 10m 10GBASE-CX1
RJ45 10GBASE-T copper Cat6, Cat6A, Cat7 100m 10GBASE-T


Small Form-Factor Pluggable (SFP) technology provides cost-effective and flexible options for server network interface cards (NICs) and ToR switches. The SFP+ direct attach copper solution is a fully integrated SFP+ cable that is available in multiple lengths up to 10 meters. 10G SFP+ copper Twinax (SFP+ CU copper) is currently the best choice for server connectivity, providing a robust, power-efficient, and cost-effective solution for 10 Gigabit Ethernet transmission.

Cisco SFP+ DAC

10GBASE-T was released by IEEE 802.3an in 2006 which specifies 10Gbps data transmission over four-pair copper cabling. Category 6A (Cat 6A) copper cabling is recommended to use with the 10GBASE-T standard to achieve reliable 10Gbps operation over 100m copper twisted-pair channels. 10GBASE-T has higher latency and consumes more power when compared to 10GBASE-CX1 and optical technologies. But this has been changed as the technology matures. 10GBASE-T solution is considered as an ideal copper cabling option for long-term plan.

10 Gigabit Ethernet Over Fiber

Fiber cabling becomes popular with the benefit of delivering the lowest latency in 10 Gigabit Ethernet. It is typically used for longer distance connectivity and environments that need protection from interference. There are two different types of optical fiber—multimode (MM) and single-mode (SM). For 10 Gigabit Ethernet server connectivity, multimode cabling is preferred to use with the following options:

Connector (Media) Cable Max. Distance Wavelength
10GBASE-SR SFP+ OM2/OM3 300m 850nm
SFP+ to SFP+ Active optical cable 100m \


For EDA (Equipment Distribution Area) to HDA (Horizontal Distribution Area) horizontal connectivity, SFP+ short-reach (SFP-10G-SR) cabling is better suited for longer distance connectivity between the server (EDA) rack and network equipment racks located in the HDA. It provides cost-effective fiber connectivity for fiber-based server connectivity options. In addition, SFP+ to SFP+ AOC (Active Optical Cable) is also an ideal choice for server connectivity due to its similar performance with the short-reach transceiver but with low cost.

Cisco SFP-10G-SR


10 Gigabit Ethernet has established itself as the ideal foundational technology. For server connectivity, copper and fiber cabling are available. Considerations for use cases depend on variables including latency, distance, power consumption, cost, and so on. FS.COM offer a wide range options of reliable 10Gigabit transceivers. For more information, please contact

Things You Should Know About Direct Attach Cables

Things You Should Know About Direct Attach Cables

DAC-Direct Attach CableDirect Attach Cable, short for DAC, is a form of high speed cable with “transceivers” on either end. They can be used to connect switches to routers or servers . They are becoming increasingly popular in the network industry and widely applied in storage area network, data center, and high-performance computing connectivity etc. The main reason why DAC is popular in the market is the price difference, compared with the regular optics. Another reason for their increased popularity is that RJ-45 10G is not widely adopted, and most high density 10G switches are delivered with 48x SFP+ ports in 1 Rack Unit. Here are some knowledge you may not know but should know about the DACs.

1. No matter in the related article or in product description of some DACs vendors, there is always a point saying that the active DACs are lighter and thinner than passive DACs. Actually, it is a wrong view of point. If you have an using experience of both active and passive DACs, you may find that there is no difference between them in the weight and appearance.

2. As the first point mentioned, the thickness and weight do not depend on the active or passive function. In fact, they are divided according to their characteristic of AWG (American Wire Gauge). For instance, AWG24 DAC is thicker and heavier than the AWG30. Becuase of the difference of wire diameter, the longer the cable, the more inconvenience AWG24 DAC is, compared with the AWG30. Moreover, there is also limited bend radius. Thus, the longer the distance, the higher the AWG rating should be.

3. When the transmission distance is over 5 metres, active DAC is more suitable than passive DAC. Because it will cause the signal issue when using passive DAC for long-haul transmission.

4. DACs are more cheaper than the regular optics. Because the “transceivers” on both ends of DACs are not real optics. Compared with the regular optics, they are without the real components and just used to transmit the optical signals. And of course, without those expensive optics components, the cost of DACs is much lower. Thus, though using the same port as an optical transceiver, DACs are with significant cost savings and power savings in short reach applications.

5. The main difference between active DAC and passive DAC is that there is a driving chip in the design of active DAC.

active vs passive DACs

6. AOC (Active Optical Cable) is one of the form of DAC which integrates multimode optical fiber, fiber optic transceivers, control chip and modules. With the benefits of AOCs, such as lighter weight, high performance, low power consumption, low interconnection loss, EMI immunity and flexibility etc. AOCs are now considered as the rising star of telecommunications and datacom transceiver markets.


Fiberstore offers a variety of high speed interconnect DAC assemblies including 10G SFP+ Cables, 40G QSFP+ Cables, and 120G CXP Cables to satisfy the demands from 10G to 100G interconnection. All of the Fiberstore’s direct attach cables can meet the ever growing need to cost-effectively deliver more bandwidth, and can be customized to meet different requirements. For more information, please visit or contact over e-mail

Six Types of QSFP+ Cables

Six Types of QSFP+ Cables

QSFP+ cables provide a high density, high bandwidth, cost effective solution for a variety of markets and applications including switches, routers, HBA’s, high performance computing and mass storage sub-systems by mfr’s such as IBM, Cisco, qLogic, etc. QSFP+ cables are designed for data rates up to 40Gb/s supporting Fibre Channel, Ethernet, SDH/SONET and Infiniband standards.FiberStore provide a wide variety of 40G QSFP+ Cables,including 40G QSFP+ copper cables, 40G QSFP+ AOC cables, QSFP+ to 4 SFP+ Breakout Cables, QSFP+ to CX4 Copper Cables, QSFP+ to 4 XFP Cables and QSFP+ to Mini SAS cables with different lengths and wire gauges. OEM and ODM are welcomed.

40G QSFP+ Copper Cables:

QSFP+ (Quad Small Form-factor Pluggable Plus) Cable Assemblies are suitable for very short distances and offer a highly cost-effective way to establish a 40-Gigabit link between QSFP+ ports of QSFP+ switches within racks and across adjacent racks. QSFP+ cables are used for 40 GbE and Infniband standards, to maximize performance. We now provide several lengths to accommodate your installation requirements, welcome to buy it from FiberStore.We offer the 40G QSFP+ copper cables with lengths ranging from 0.5m to 10m.

40G QSFP+ AOC Cables:

QSFP+ Active Optical Cable (AOC) is a high performance, low power consumption integrated cable for short-range multi-lane data communication and interconnect applications, supporting 40G Ethernet, fiber channel and PCIE. It is compliant with the QSFP MSA and IEEE P802.3ba 40GBASE-SR4. It integrates four data lanes in each direction with 40 Gb/s aggregate bandwidth. Each lane is capable of transmitting data at rates up to 10Gb/s with lengths ranging from one to 100 m.

QSFP+ to 4 SFP+ Breakout Cables:

QSFP+ to 4 SFP+ hybrid splitter cables make a great cost-effective interconnect solution to IT professionals by providing much needed space for data centers and cost cuts. These cables allow you to connect your QSFP+ and SFP+ Switches and Network cards without upgrading your entire data center or storage array. They can be used for QDR infiniBand, 40 Gigabit Ethernet and 10Gigabit applications. Each QSFP-SFP+ splitter cable features a single QSFP connector (SFF-8436) rated for 40-Gb/s on one end and (4) SFP+ connectors (SFF-8431), each rated for 10-Gb/s, on the other. We now provide several lengths to accommodate your installation requirements.

QSFP+ to CX4 Copper Cables:

The QSFP to CX4 cables use cutting edge technology to provide an excellent hybrid cable solution for CX4/InfiniBand and QSFP rated switches, network adapters, and storage arrays. These cables have a QSFP connector on one end and a CX4 Connector on the opposite end.

Each CX4-QSFP copper cable has the following features:

a. Permits auto-negotiation between the two connected devices for optimal network throughput.

b. Reaching data rates of up 5Gpbs per channel.

c. Compatible with 4x Infiniband SDR/DDR and 10 GbE applications.

For this kind of QSFP to CX4 Direct Attach Passive Copper Cable, we now provide several lengths to accommodate your installation requirements.

QSFP+ to 4 XFP Cables:

QSFP+ to 4 XFP hybrid splitter cables make a great cost-effective interconnect solution to IT professionals by merging 40G QSFP and 10G XFP enabled host adapters, switches and servers. For typical applications, users can install this kind of splitter cable between an available QSFP port on their 40-Gigabit/s rated switch and feed up to four upstream 10GbE-XFP enabled switches. Each QSFP-XFP splitter cable features a single QSFP connector (SFF-8436) rated for 40-Gb/s on one end and 4 XFP connectors (INF-8077i) on the other end, each rated for 10-Gb/s.

QSFP+ to Mini SAS Cables:

QSFP+ to Mini SAS (SFF-8088) hybrid cables are designed for high-density Serial Attached SCSI (SAS) applications. These Mini SAS Cables are used as an interconnect solution between newer QSFP+ Hardware and older external 3G and 6G Mini SAS equipment and provide data transfer rates up to 10Gbops per channel at distances of up to 10 meters, and they are all compliant to QSFP+ Multi-Source Agreement. Welcome to choose it from our website where different lengths can be selecting.

Fiberstore is a professional fiber optic products supplier and manufacturer,we provide a wide variety of fiber optic products, we not only have the 40G QSFP+ Cables, but also have other types Direct Attach Cables. If you can’t find your need in my company, you can contact to our sales, because we offer the customized service. Welcome to Fiberstore,I think it can help to solve your fiber optic problem.