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目前显示的是 八月, 2015的博文

Things You Need to Know about MUX and DEMUX

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The request of unveiling the secrets of MUX and DEMUX recently forces me to give a clearer presentation to those who have great interest in telecommunication field. The following passage will be focused on a brief synopsis to MUX and DEMUX. I hope you can learn something from it. What are MUX and DEMUX?
In electronics, a multiplexer (or mux) is a device that selects one of several analog or digital input signals and forwards the selected input into a single line. Conversely, the data distributor, known commonly as a demultiplexer or demux for short, is the exact opposite of the multiplexer. It is a device taking a single input signal and selecting one of many data-output-lines, which is connected to the single input. How do They Work?
As we knew before, a multiplexer is often used with a complementary demultiplexer on the receiving end. Look at the circuit. It consists of a multiplexer (MUX) at the transmitting side and a demultiplexer (DEMUX) at the receiving side. A multiplexer is a …

Which Option Is Best for You – CWDM or DWDM?

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Today’s world witnesses an era of fiber optic cabling for users intensively requiring more bandwidth and faster transmission rates over ever increasingly distance. In the field of telecommunications, data center connectivity and video transport, fiber optic cabling is highly desirable due to the enormous bandwidth availability, as well as reliability, minimal loss of data packets, low latency and increased security. However, the reality is that the fiber optic cabling is no longer an economical or feasible choice to implement for each individual service. Thus using a Wavelength Division Multiplexing (WDM) for expanding the capacity of the fiber on the existing fiber infrastructure is highly advisable. WDM is a technology that multiplexes multiple optical signals onto a single fiber by using different wavelengths of laser light. A quick study of WDM fields will be put on CWDM and DWDM. They are based on the same concept of using multiple wavelengths of light on a single fiber, but the…

Comparison between QSFP-40G-LR4 and QSFP-40G-PLR4

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Times are always moving forward, just as data center regularly goes through great migration from 1G, 10G to 40G, 100G over the past few decades. Since IEEE 802.3ba standard defined the 40G Ethernet on June 17, 2010, people designed several types of 40G optical transceivers to achieve 40G network, of which QSFP is the most common type available in the market. There are many different variants, like QSFP-40G-LR4, QSFP-40G-PLR4. So what is the difference between them? The following passage will provide a satisfying answer for you.
QSFP-40G-PLR4
As the word implies, one obvious difference between QSFP-40G-LR4 and QSFP-40G-PLR4 is that QSFP-40G-PLR4 has a plus letter “P” in it. In fact, it means parallel. As we all know, in digital data transmission, data transmission usually occurs in two modes—serial and parallel. Parallel transmission is the simultaneous transmission of multiple bits over two or more separate paths, which allow for higher data transfer rates than can be achieved with se…

Introduction to Cisco QSFP-40G-SR4 and QSFP-40G-CSR4

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Are you feeling irritated about the internet speed? Especially, when you encounter the following situations. First, you have to buffer constantly when watching the video, refreshing continuously while browsing the page and you have to wait for so long to download music or other things. What’s worst, you even can’t do anything over the internet. A good news is that 40G Ethernet will solve your problems. It offers higher bandwidth and greater internet speed. 40G optical transceiver, especially, 40G QSFP transceiver, as an essential component to support 40G network, will be introduced in this passage. QSFP transceiver is mainly used in 40G network. It is a compact, hot-pluggable transceiver used for data communications applications. QSFP interfaces networking hardware to a fiber optic cable. Compared with SFP, QSFP transceiver increases the port-density of 3-4 times and integrates 4 independent 10 gigabit per second data lanes in each direction to provide 40Gbps bandwidth. The QSFP tran…

Four Common Types of Fiber Optic Connectors

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The introduction of fiber patch cables has allowed the realization of much greater rates of data communications with higher signal. And we can see a lot of fiber patch cables available in the market, such as LC to LC fiber cable, single mode LC to ST fiber patch cable, single mode fiber ST to SC patch cord, single mode fiber cable with LC connector, etc. Customers may wonder what LC, ST, SC refer to. In fact, those refer to the different types of fiber optic connectors. A fiber optic connector terminates the end of a fiber optic cable, and enables quicker connection and disconnection than splicing. It has to be aligned properly to the microscopic glass fibers completely in order to allocate for communication. In all, there are nearly 100 fiber optic connectors in the market, but only a few represents the majority of the market — LC connector, SC connector, ST connector, FC connector etc. Next, some detail information about the above connectors will present to you. SC Fiber Optic Conne…

A Closer Look at Simplex and Duplex Fiber Patch Cable

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When talking about fiber optic patch cable, related products that firstly come to our mind are usually multimode and single mode fiber patch cable. However, there are still many other types, such as multimode 50 125 duplex fiber patch cable LC LC, LC to LC duplex single mode patch cable and single mode simplex fiber. Beginners in this field might wonder what duplex and simplex fiber patch cables are. This text will introduce you about these cables. Before we come to simplex and duplex fiber patch cables, let’s firstly get familiar with the two words — simplex and duplex. What Do Simplex and Duplex Mean?
According to the ITU-T definition, a simplex circuit is one where signals can flow in only one direction at a time. One end is the transmitter, while the other is the receiver and that is not reversible. For example, in TV, audio or visual information flows from transmitter to numerous receivers. However, at other times, communications can flow in the reverse direction. That is half-du…

Guide to SFP Transceiver for Gigabit Ethernet

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Introduction of SFP Transceiver  The small form-factor pluggable (SFP) transceiver is a compact, hot-pluggable transceiver used for both telecommunication and data communications applications. SFP interfaces network devices, such as switch, router, media converter or similar device, to fiber optic or copper networking cable. The SFP is also called Mini-GBIC due to the fact that SFP obsolesces the formerly ubiquitous gigabit interface converter with its small size.
Gigabit Ethernet Standards Gigabit Ethernet (GbE or 1 GigE), defined by the IEEE 802.3-2008 standard, is a term describing various technologies for transmitting Ethernet frames at a rate of a gigabit per second (1million bits per second). There are a variety of Gigabit Ethernet Standards. A table is listed below to offer you a visual impression of the standards of Gigabit Ethernet.
NameMediumSpecified distance1000BASE-CXShielded balanced copper cable25 meters1000BASE-KXCopper backplane1 meter1000BASE-SXMulti-mode fiber220 to 5…