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Category: LC/SC/MTP Patch Cables

How Does LC Uniboot Patch Cord Reverse Polarity?

How Does LC Uniboot Patch Cord Reverse Polarity?

uniboot-HD-LCDLC Uniboot patch cords are now used as the preferred option of fiber patch cords for data center high density connectivity. They feature a reverse polarity uniboot designed LC connector, eliminating the need for the dual zip cord and reducing overall cabling bulk by 50%. But do you know how does the LC uniboot patch cord achieve polarity reversal? You may find the answer in this post.

Brief Introduction to LC Uniboot Patch Cord

LC uniboot patch cords are designed for high density applications in data center environment. Generally, the LC uniboot patch cord is designed with a polarization method that can help users easily reverse the fiber polarity. In addition, the LC uniboot fiber patch cord can reduce cable management space comparing to standard patchcords as it places both simplex fibers into one jacket while still terminating into a duplex LC connector. Similar to the standard patch cord, single-mode and multimode versions are available in LC uniboot patch cord.

Basic Types of Design Principle

As we know, for traditional cabling systems using single fiber connectors, maintaining polarity requires that the “B” transmit signal connects to the “A” receive signal. But duplex patch cords used to complete serial duplex pair connections are available in two types, depending on which polarity technique is used—”A-to-B” patch cord for “straight-through” wiring and “A-to-A” patch cord for “crossover” wiring. Thus, polarity reversal is usually required during fiber optic cabling.

However, for traditional LC patch cord, polarity reversal is very inconvenient. Therefore, vendors developed the LC uniboot that is easier for polarity reversal, without having to re-terminate the connectors. Nowadays, throughout the market, two basic types of design principle are mainly used in LC uniboot patch cord for polarity reversal.

  • Type One: Switching the A and B positions of the patch cord
    LC Uniboot switchable
  • Type Two: Rotating connector 180 degree to exchange the position
    LC Uniboot 180 degrees
Products in the Market

Based on the above two design principles, there are various of LC uniboot patch cord products in the market now. In type one, the early LC uniboot patch cord requires stop-ring and kevlar crimp sleeve for the best cable retention support. But now, switchable LC uniboot patch cords with more convenient design are launched to the market. Users can open the clip and switch the polarity easily without any tools during the whole process. Products based on type two design principles apply some separation and rotation on the connectors to achieve the polarity reversal, instead of A and B position exchange. According to different vendors, the rotating part may be in a different design, e.g. Flip the released section of the housing or separately turn the A and B connector 180 degrees in the corresponding direction.


At present, a variety of LC uniboot patch cords are on sale in the market. Though they are designed based on the above two principles, they have different features according to different vendors. Famous vendors such as Levtion, Panduit, FS.COM, SENKO, etc., can offer LC uniboot patch cords. Users can choose a reliable vendor and choose the type you preferred according to the actual requirement.

Understanding Fiber Polarity Method: Which to Choose?

Understanding Fiber Polarity Method: Which to Choose?

40G and 100G are now universally deployed in data centers. As the preferred array-based fiber connector option, the MPO/MTP connector and its cable assemblies are widely used for 40/100G connectivity in high-density data center environments. However, in complex high density cabling, the advantages of MPO/MTP cabling will be lost if you don’t have a proper polarity method. Thus, the TIA 568 standard provides three methods—Method A, B and C, for configuring systems to ensure that proper connections are made. In this blog, these three methods would be described in details which may guide you to select the best method for ensuring polarity across your array-based fiber installation.

Understanding MPO/MTP Basic Structure

Before looking at each method in detail, it is necessary to understand the basic structure of an MPO/MTP connector. As the following picture shows, an MPO/MTP connector contains several parts such as boot, coupling/housing assembly, ferrule, guide pins, and so on. When the MPO/MTP connector is designed with pins, it is called male connector. On the contrary, it is called female connector.

MPO MTP structure

In addition, there is a “key” on one side of the connector body. When the key sits on top, we call that it is the key-up position. In this orientation, each of the fiber holes in the connector is numbered in sequence from left to right. We will refer to these connector holes as positions, or P1, P2, etc. Generally, there is a marker called “white dot” on the side of the connector body that is used to designate the position 1 side of the connector when it is plugged in.

Polarity Method Introduction

The TIA-568-C.0 standard illustrated three array system connectivity methods—Method A, Method B and Method C. This section will introduce them respectively.

Method A
As shown in the picture below, two Method A cassettes with key-up to key-down adapters, a straight-through key-up to key-down MPO trunk cable as well as two patch cables are required in Method A connectivity. The straight-through key-up to key-down MPO trunk cable means that the fiber 1 located in P1 of the connector on the left will arrive at P1 at the other connector. What’s more, it should be noted that the transmit‐receive flip must happen in the patch cables for Method A. In other words, an “A-to-A” patch cable at one end of the connection while an “A-to-B” patch cable at the other end.

Method A

Method B
In Method B, as shown in the following picture, Method B cassettes which employs key-up to key-up adapters are required to link straight-through key-up to key-up MPO trunk cable. With the key up on both ends, the key-up to key-up trunk cable has a different fiber array with Method A type cable. In this type of trunk cable, fiber 1 (Tx) is mated with fiber 12 (Rx), fiber 2 (Rx) is mated with fiber 11 (Tx), and so on. Two straight “A-to-B” patch cables are required at the beginning and end of the link, namely patch cables do not need to be flipped in Method B.

Method B

Method C
Method C uses the same cassettes as Method A, but to link a special key-up to key-down trunk cable. For Method C, each adjacent pair of fibers at one end are flipped at the other end. Notice the swapping of the color positions in the picture below. Fiber channel is completed by utilizing straight “A-to-B” patch cables at the beginning and end of the link. Method C is similar with Method A. The only difference between this method and Method A is that the pair-wise flip occurs in the array cable itself rather than at the patch cables, so that odd-numbered Tx fibers leaving the near-end cassette are in even-numbered Rx positions when they arrive at the remote cassette, e.g. fiber 1 (Tx) is mated with fiber 2 (Rx).

Method C

Which to Choose?

The above section shows us the details of these three methods. The following table summarizes the advantages and disadvantages of them which may guide you to choose a proper one for your network. But, it is very important to know that the method choice should be maintained consistently throughout the installation. Do not mix them throughout the installations.

Method Pros Cons
A One cassette type, easy to produce and purchase Requires pre-configured “A-to-A” patch cables, or field configuration of same
Compatible with many legacy systems
Multiple sources for components
Industry standard
Single-mode and multimode
Standard provides migration path to parallel optics
Ribbon cables can be linked (need male/female connector)
B Single source for components Remote cassette must be flipped and re-labeled
“A-to-B” patch cable only Identification and maintenance of cassettes are different on each end
Industry standard Multimode only
Standard provides migration path to parallel optics Not compatible with legacy systems
Ribbon cables can only be liked using less available (Key Up to Key Up) adapters (need male/female cable)
Fewest vendors
C One cassette type, easy to produce and purchase Less reliable than Method A
Singlemode and multimode Specialized ribbon cable assembly
Industry standard Does not support parallel optics
“A-to-B” patch cable only Not compatible with legacy systems
Less vendor support than Method A
Difficult to extend link

This post introduced three array system connectivity methods and listed their pros and cons that may guide you for polarity selection. In a word, the Method A is polarity flip in A‐to‐A patch cord. The Method B is polarity flip in cassette. And the Method C is flip by pairs. When choosing one of them for your network, the most critical consideration is to select one method and stick with it.

Polarity and MPO Technology in 40/100GbE Transmission (FS.COM)
ANSI/TIA-568-C.0 Standard
Best Practices for Ensuring Polarity of Array-Based Fiber Optic Channels (PANDUIT)

Understanding Fiber Polarity Method: Which to Choose?

24-fiber MPO/MTP Solution – the Right Migration Path to 40/100 GbE

24-fiber MPO/MTP Solution – the Right Migration Path to 40/100 GbE

MPO-MTP-CableNowadays, many data center are migrated to 40/100 GbE (Gigabit Ethernet) from 10 GbE in order to meet the increasing demands on high speed and bandwidth. 12-fiber and 24-fiber MPO/MTP cable, as the necessary assemblies for 40/100G migration are now applied in many solutions. 12-fiber multimode trunk cables are more often recommended to use between core switched and the equipment distribution area in the data center. But is the 12-fiber the best migration path? This article will give the opposite answer—24-fiber trunk cables may be better.

A 12-fiber MPO/MTP connector is used for 40 GbE (data rate up to 40Gbps, 4 x 10 Gbps). But among the 12 fibers, only 8 optical fibers are required—4 for Tx and 4 for Rx, and each channel has a transmission rate of 10 Gbps (usually use the 4 left and 4 right optical fibers, and the inner 4 optical fibers are left unused). And for 100 GbE (data rate up to 100 Gbps, 10 x 10 Gbps or 4 x 25 Gbps), there are two solutions. One is to use two 12-fiber MPO/MTP connectors, one transmitting 10 Gbps on 10 fibers and the other receiving 10 Gbps on 10 fibers. The other one is to use a 24-fiber MPO/MTP connector. Among the 24 fibers, only 20 fibers in the middle of the connector are used to transmit and receive at 10 Gbps and the 2 top and bottom fibers on the left and right are unused.


Is there anything wrong with the above solution? Why said the 24-fiber is better than 12-fiber? Actually, it all comes down to a better return on investment and reduced future operating and capital expense. Just see the following four advantages, you will believe it.

Advantage 1: Maximum Fiber Utilization

Using 24-fiber trunk cables with 24-fiber MPO/MTP connectors on both ends to connect from the back of the switch panel to the equipment distribution area can maximum the fiber utilization. For 10G applications, each of the 24 fibers can be used to transmit 10 Gbps, for a total of 12 links. For 40G applications, which requires 8 fibers (4 Tx and 4 Rx), a 24-fiber trunk cable provides a total of three 40G links. For 100 GbE, which requires 20 fibers (10 Tx and 10 Rx), a 24-fiber trunk cable provides a single 100G link (24-fiber solution is the more recommended configuration to used for 100 GbE than 12-fiber solution). This recoups 33% of the fibers that would be lost with 12-fiber trunk cables, providing a much better return on investment.

Advantage 2: Reduced Cable Congestion

24-fiber trunk cables provide more amount of fiber in less space. For instance, it takes three 12-fiber trunk cables to provide the same number of links as a single 24-fiber trunk cable—or about 1-1/2 times more pathway space for a 40G application.

Advantage 3: Increase Fiber Density

Density in fiber switch panels is critical as today’s large core switches occupying upwards of 1/3 of an entire rack. 24-fiber MPO connectors offer a small footprint which can ultimately provide increased density in fiber panels at the switch location. In addition, with fanout technology, a 24-fiber MPO patch cable can be designed with a 24-fiber MPO on one end and 12 duplex LCs on the other end which is an ideal solution for high density 40/100 GbE migration.

Advantage 4: Simple and Cost-effective

24-fiber MPO/MTP solution is a simple and cost effective migration path from 10G to 40/100G Ethernet. It effectively supports all three applications—10, 40 and 100 GbE. Data center managers can easily migrate to higher speeds, with less time and complexity, as 24-fiber solution offers guaranteed performance for 10, 40 and 100G applications, upgrading the cabling infrastructure is as simple as upgrading the fan-out cables or cassettes and patch cords to the equipment.

This year, 40/100G will become more universal. Choose the right migration path can help reach maximum benefit and save more budgets. Meanwhile, choose a good vendor for your 40/100G optics is also necessary. The same as usual, Fiberstore may be your good choice.

High Density Push-Pull TAB Fiber Patch Cables

High Density Push-Pull TAB Fiber Patch Cables

With the ever-increasing demand for IT resources, data centers should also grow to keep the pace with customers’ needs. However, adding more floor space is an expensive, disruptive and sometimes un-affordable solution. Therefore, engineers prefer to increase the power density of the data center by using high density products. Among the various high density products, push-pull TAB fiber patch cables may be unimpressive, but they do provide improved accessibility, reduced installation costs and outstanding performance for today’s demanding high-density data center applications. This article gives an overview of the high density push-pull TAB patch cables.

What Is Push-Pull TAB Fiber Patch Cables?

The push-pull TAB fiber patch cable is a totally unique design, which features push-pull tab connector that offers maximum accessibility in high density installations. With this kind of fiber patch cables, technicians may finish the installing and removing procedures with only one hand and no additional tools are needed. Now there are mainly two kinds of push-pull TAB fiber patch cables in the market : LC-HD TAB fiber patch cables and MPO-HD TAB fiber patch cables. The LC-HD TAB fiber patch cable is designed for the LC-HD switchable& movable connector. And its slim uni-boot design saves much space and makes cables more easily to be managed. MPO-HD TAB fiber patch cables, with their MTP/MPO connectors that can accommodate 12 fibers, provide up to 12 times the density, thereby offering savings in circuit card and rack space.

LC-LC Push Pull Cables MTP-MTP  Push Pull Cables
Why Push-Pull TAB Cables Are Superior for Density Applications?

Though traditional patch cables are also popular in the data center, the push-pull TAB patch cables are superior in some aspects.

No Adverse Effects on the Cord’s Electrical Performance

Before push-pull TAB patch cables are developed, technicians often have great difficulty in releasing connectors and managing the density of cabling. Sometimes, they may need to use screwdrivers to unlatch patch cords in a densely populated network space. Obviously, much can go wrong when a technician wields screwdrivers around networking gears. Push-pull TAB patch cables do not require any manual latching. technicians just need to push the tab forward to latch and gently pull the tab to release. This allows technicians to unplug the cord by pulling on the boot in a process that has no adverse effects on the cord’s electrical performance.

Easy to Release Patch Cord

In high-density environment such as 48-port 1U patch panels, inserting and disconnecting patch cords can be challenging for technicians. The flexible pull-tab of the patch cable allows for the connector to be disengaged easily from loaded panels without the need for special tools. In fact, a gentle pull on the tab may disengage the connector from extremely dense fiber optic panels. Furthermore, labeling is also available on the pull-tab so that each cable can be quickly identified.

remove lc-hd
Much More Increase in Density

Since the connector of the patch cable can be removed using a simple pull tab, it eliminates the need for finger access to the connectors latch mechanism, therefore adapters can now be mounted much closer than spacing required in the past.

Space Saving

The traditional connectors often require a small vertical space above and below the adapters. While the low profile push-pull TAB patch cable, together with it’s pull tab, allow adapters to be stacked with absolutely no vertical space (as in the following figure).

dense mpo-hd

In today’s data centers, improving network capacity and space utilization is more important than ever. And push-pull TAB fiber patch cables are certainly among the ideal high density solutions. Fiberstore offers a wide range of push-pull TAB patch cables that will help free up space.We supply simplex&duplex LC-HD patch cords, 12&24 fibers MPO-HD patch cords, MPO-LC harness cables, providing low-loss performance for multi-mode and single mode high speed networks and improving network performance. All these products are most suitable for patching high density blade servers, patch panels and equipment.

What You Should Think About Before Selecting Fiber Cables

What You Should Think About Before Selecting Fiber Cables

Sorting through cables and connectivity options could be a frustrating exercise. It’s hard enough working through the categories and levels of copper networking cables, where most cables end with similar connector. What happens when you start looking at fiber cables? This is where things can definitely get confusing! This article tells you how to select the right kind of fiber cables.

Let’s move on off by saying that fiber optic cables can be used in a huge variety of applications, from small office LANs, to data centers, to inter-continental communication links. The information lines that connect between North America and Europe, for example, are constructed with fiber optic cable strung underneath the ocean. Our discussion in this article will focus mainly on the kinds of cables present in those small-scale networks closer to home, and in particular to pre-terminated cables which may be designed for installation, called “patch cords”, “pre-terms”, or any other similar nicknames like fiber patch cables. Prior to you buying, you should make clear the following parameters.

Multimode and Single mode
One of the first things to determine when selecting fiber optic cables is the “mode” of fiber that you’ll require. The mode of a fiber cable describes how light beams travel within the fiber cables themselves. It’s important because the two modes aren’t compatible with each other, which means that you can’t substitute one for that other.
There’s really not much variety with single mode patch cords, but there’s for multimode. You will find varieties described as OM1, OM2, OM3 and OM4 (OM means the “optical mode”). Basically, these varieties have different capabilities around speed, bandwidth, and distance, and the right type to make use of will be based mostly upon the hardware that is being used with them, and any other fiber the patch cords will be connecting to.

Fiber Optic Cable Jackets
Pre-term fiber can be used in a variety of installation environments, and as a result, may need different jacket materials. The standard jacket type is called OFNR, which means “Optical Fiber Non-conductive Riser”. This can be a long-winded way of saying, there’s no metal in it, so it won’t conduct stray electrical current, and it can be installed in a riser application (going in one floor up to the next, for instance). Patch cords are also available with OFNP, or plenum jackets, which are ideal for use in plenum environments for example drop-ceilings or raised floors. Many data centers and server rooms have requirements for plenum-rated cables, and also the local fire codes will invariably have the final say in what jacket type is required. The ultimate choice for jacket type is LSZH, which means “Low Smoke Zero Halogen”, that is a jacket produced from special compounds that provide off very little smoke with no toxic halogenic compounds when burned. Again, seek advice from the neighborhood fire code authority to be certain of the requirements from the installation before making the jacket selection.

Simplex and Duplex
Simplex and duplex have only the difference between one fiber or two, and between one connector at each end of the cable, or two connectors each and every end. Duplex patch cords are the most common type, because the method in which most fiber electronics work is they need two fibers to speak. One is used to transmit data signals, and the other receives them. However, sometimes, just one fiber is required, so simplex patch cords may be essential for certain applications. If you aren’t sure, you can always be on the safe side by ordering duplex patch cords, and just one of these two fibers.

Fiber Optic Cable Connectors
Remember what we should said at first about copper category cables? No matter what level of twisted pair you were coping with (Cat 5, 5e, etc), you always knew you would be dealing with an 8-position modular RJ-45 plug around the end from the cable. Well, with fiber patch cords, there is a few possibilities when it comes to connectors. The common connector types are FC, LC, SC, ST and MTRJ etc..

These are the most typical selections that you will find when choosing amongst patch cords. If you’re able to determine which of these characteristics you need, it is highly likely you will make the right choice when custom fiber optic cables with suitable parameters.