Tag Archives: direct attach cable

The Advantages Of QSFP+ PSM4 AOC

40G QSFP+ AOC has been introduced Few days ago,Today we are going to introduce Fiberstore’s QSFP+ (Quad Small Form-factor Pluggable Plus) PSM4 (Parallel Single Mode Quad) Active Optical Cables (AOCs) which use a Silicon Photonics (SiPh) optical engine and use lower cost singlemode fiber for transmission distances up to 4km. QSFP+ cables are used for 40GBASE and Infniband standards, to maximize performance.Whether QSFP+ PSM4 AOC and 40G QSFP+ AOC, is one of the Direct Attach Cable.


Multiple forces are driving the implementation of PSM4 and SiPh in next generation data-center designs and architectures. PSM4 and SiPh fill an important gap in data-center interconnect options, the gap between the reach of 25G multimode options and that of Long Range (LR) optical approaches. Using pigtail designs with these technologies can ease implementation via easy mating to structured cabling. From a futureproofing perspective, PSM4 is an approach that can accommodate both current and future bandwidth upgrades. A SiPh-based PSM4 approach helps resolve the multiple challenges of higher bandwidth, longer distances, low power, and futureproofing. SiPh-based LR PSM4 products offer seven primary advantages.

Distance: With transmission distances up to 4 km, they can accommodate most, if not all, new data-center requirements. Power: SiPh-based AOCs use basically the same power consumption as VCSEL-based products: under 1 W for a 10G QSFP+ AOC and 1.5 W at 25 Gbps. Cost: The cost is roughly the same as VCSEL-based AOCs, but since they are single mode (SM), they use much less expensive SM cable. As speeds increase, VCSEL-based products require ever more expensive types of fiber. After most networks have upgraded to OM3, an upgrade to OM4 can be costly. And what comes after OM4, and how soon will it be needed? With SM SiPh AOCs, the fiber remains inexpensive SM and stays consistent as data rates increase. Futureproof Structured Cabling: Upgrading structured cabling is less economically viable as speeds continue to increase. PSM4 can accommodate 10 GbE, 40 GbE, 4×10 Gbps aggregated QDR Infiniband, 4×14 Gbps FDR Infiniband, 100 GbE, 4×25 Gbps aggregated. Pigtail Plug-in Options for Ease of Installation and Upgrades: PSM4 AOCs are available in pigtail versions. Here, one end is a traditional QSFP+ active interface and the other either MPO or LC connectors. This enables a quick connection to structured cabling (so the AOC side doesn’t have to be pulled long distances) and the ability to quickly upgrade as needed with no costly structured cabling upgrade and associated data-center downtime. SiPh Actives Becoming Broadly Available: An ecosystem of proven, reliable, cost-effective SiPh devices exists to accommodate SM data-center links. SiPh is widely deployed today in PSM4 AOCs, and several new entrants into the market are offering a variety of options. SiPh Offers a Path Beyond 25G: VCSELs face increasing challenges as speeds increase. With SiPh-based systems, most modulating schemes have a clear and well-understood technology path to 50G, 100G, and beyond.

SM SiPh bridges the gaps caused by the dual requirements of longer distances and higher data transmission speeds. With a broad base of products both available and being developed by multiple suppliers, PSM4 and SiPh AOCs can be deployed today to enable new data-center architectures, with the assurance that they’ll provide a path to cost-effectively meet future upgrade requirements.

Fiberstore offers 40GBASE QSFP+ to QSFP+ active optical cables with lengths of 10m to 100m.Lengths and compatible brands can be customized up to customers’ requirements.So,if you or your friends want to buy qsfp 4x10g aocs, Fiberstore could be your first choice!

Article source:http://www.fs.com/QSFP+-PSM4-Active-Optical-Cables-Tutorial-aid-402.html

SFP+ Direct Attach Cable Wiki

Today, SFP+ Direct Attach Copper (DAC) cable becomes cloud computing and cloud storage mainstream primary connection tool, but what is DAC cable? For this, different manufacturers of DAC cable have different presentations and descriptions. And here, we’ve got a number of related information together, mainly to discuss what exactly is SFP + DAC cable also it other details, as well as discuss the advantages and disadvantages between Active and Passive SFP + cable.

Introduction of SFP+ Cable

The SFP+ interface provides the highest density, cheapest, and lowest power 10 Gigabit Ethernet solution commercially available today. Further SFP+ enables mass migration of the 1GbE network to 10 GbE by providing an extremely low priced 10G SFP+ Cu (direct attached copper cable assembly) option for short reach interconnects along with multimode and single mode fiber options. The SFP+ interface accepts along with hot-pluggable, small-footprint, optical transceivers, a Direct Attach Cable (10G SFP+ Cu), which replaces two optical modules and a connectorized optical fiber with a twinaxial copper cable assembly. The 10G SFP+ Cu option is defined for 10GbE applications over passive copper with a reach of 8.5m. The 10G SFP+ Cu link utilizes a receive equalizer from the host PHY/SerDes to be able to compensate for the Inter Symbol Interference (ISI) introduced by the cable. Electrical and mechanical specifications for SFP+ optical modules, 10G SFP+ Cu, and hosts are defined in the SFF-8431 specification developed by the SFF Committee, with broad industry participation.

What’s DAC Cable

10G SFP+ Cu(10G SFP+ Cable) is a copper interconnect using a passive twin-ax cable assembly that connects directly into an SFP+ housing. It has a range of 10 meters and like 10GBASE-CX4, is low power, low-cost and low latency with the added advantage of having the small form factor of SFP+, and smaller, more flexible cabling.SFP+ Direct Attach is known as the successor technology to 10GBASE-CX4. SFP+ Direct Attach, as implied in the name, uses SFP+ MSA and by using the inexpensive copper twinaxial cable with SFP+ connectors on both sides, provides 10 Gigabit Ethernet connectivity between devices with SFP+ interfaces. SFP+ Direct Attach has a 10 meter distance limitation, thus the target application is interconnection of top-of-rack switches with application servers and storage devices in a rack.


Pasive and Active SFP+ DAC Cables

Passive cables are much less costly but require the host to do the work of driving it properly.


  • Lower Costs
  • Higher Reliability


  • No LOS
  • No TX Disable
  • No Interrupts
  • Limited Management Interface
  • Host must drive Cu cable

Active cables provide the added benefit of being “optical-module” like.


  • Enhanced Signal Integrity
  • Longer Cable Lengths
  • Transmit Pre-emphasis
  • Active/Adaptive Receive Equalization
  • Tx Disable
  • Loss of Signal (LOS)
  • Interrupts
  • Management Interface
  • Looks like an optical module
  • Don’t have to worry about host Tx/Rx for Cu cables


  • More Expensive

You can also get the DAC cable and other Fiber Optic Transceivers easily from Fiberstore.

Direct Attach Cables For 10 Gigabit Ethernet Application

The dramatic growth of bandwidth requirements has led to the increasing worldwide use of higher-performance servers. This in turn has led to the expanding need for 10 Gigabit Ethernet(10GE or 10GbE or 10 GigE), refers to various technologies for transmitting Ethernet frames at a rate of 10 gigabits per second (10×109 or 10 billion bits per second), is rapidly gaining traction within data centers. The IEEE 802.3ae standard permits distances between physical locations up to 40 kilometers over a single-mode fiber. Both single-mode and multi-mode fiber systems can be used with 10 GbE applications.

10GbE supports both copper and fiber cabling. However, due to its higher bandwidth requirements, higher-grade copper cables are required: category 6a or Class F/ cat 7 cable for links up to 100m. Unlike previous Ethernet standards, 10 gigabit Ethernet defines only full duplex point-to-point links which are generally connected by network switches. Half duplex operation and hubs do not exist in 10GbE.

Over the years, improvements in 10GbE technology, price, and performance have extended its reach beyond enterprise data centers to midmarket networks, they confidently deployed 10GbE in their corporate backbones, data centers, and server farms to support high-bandwidth, mission critical applications.

There are many 10 Gigabit Ethernet relevant products available, and the direct attach cable(DAC) is one of them. Direct Attach Cables are widely applied in storage, data, and high-performance computing connectivity. They are used to connect one Mobility Access Switch with another when forming a stack.

Important Of Direct Attach Cable:

DAC is supported only on 10G ports. Do not insert a DAC into a 1G port;

Do not attempt to unplug the integrated copper cable from the transceiver and insert a fiber cable into the transceiver.

Common direct attach cables include SFP cables, SFP+ cables, XFP to XFP cables, QSFP+ cables, MIni SAS cables, CX4 cables. These direct attach cables can meet the ever growing need to cost-effectively deliver more bandwidth, and they can be customized in different length to meet your requirement.

10G SFP+ Cables

Small form-factor pluggable plus transceiver (SFP+) direct attach copper cables, also known as Twinax cables, are suitable for short distances up to 23 ft (7 m), making them ideal for highly cost-effective networking connectivity within a rack and between adjacent racks. 10G SFP+ Cable connects from one SFP+ slot to another, without the need for SFP+ transceivers. The Direct-Attach cable is terminated on both ends with mechanical connectors that plug directly into SFP+ slots the same as SFP+ transceiver modules to. The cable is fully passive, it does not have signal buffers or amplifiers. 10G SFP+ Cable is an economical solution for interconnecting 10 Gigabit Net Optics products, also great for making short 10 Gigabit connections between network optic product and server, network switch, and monitoring equipment that have SFP+ slots.

Direct attach cable assembly is a high performance integrated duplex data link for bi-directional communication. Have a wide selection of direct attach cables at FiberStore, there always has one meets your demand.