Power over Ethernet Switch: Passive PoE Vs Active PoE

Power over Ethernet (PoE) is a technology for wired LANs. This allows a single cable usually Ethernet cable to provide both data connection and electric power to devices such as IP cameras, NVR recorders, wireless access points, etc. A PoE switch, compared with other Gigabit network switches, has power over Ethernet injection built in. This feature allows end-user to power PoE capable devices without the need for a separate power supply or the need for an electrical outlet near the powered device. If you have read about the how-to-understand-poe-and-poe-switches, you must know clearer about the difference between PoE and PoE+ switches. However, today’s article will help you understand active PoE and passive PoE.

What is PoE Switch?

As mentioned before, a PoE switch not only supply power to devices but also carries network connection. In general, a PoE switch usually contains multiple Ethernet ports, e.g. a PoE switch with 8 ports, PoE switch with 16 ports, 24 ports PoE switch, or PoE switch with 48 ports. If you are looking for PoE switch to cover all your devices, it’s important to check the port number first.

8-port PoE managed siwtch

The following image shows the 8-port PoE managed switch.


Passive Power over Ethernet vs. Active PoE

To safeguard a voltage range, the Power over Ethernet devices must communicate according to established procedures. In simple terms, active PoE refers to any type of PoE that negotiates the correct voltage between the switch and PoE-powered device. Passive PoE does no such negotiation, and as such is always sending electric current out over the Ethernet cable at a certain voltage regardless of the device it’s going to.

Active PoE

If your PoE switch uses 48V 802.3af or 802.3at standard, it is considered to be active PoE. The power supply unit inside the active PoE switch usually tests the connection before providing the supplying voltage, meaning that PoE switch will check the power coming in, and if it doesn’t meet the device requirement, it won’t power up.

Passive PoE

Passive PoE refers to any devices using PoE that is not 802.3af or 802.3at. Unlike active PoE switch, In passive PoE, no negotiation takes place between the two devices, but instead the known cable layout is used from Standard 802.3af, mode B. Therefore, it is extremely important to know what PoE voltage your devices requires before plugging in the Ethernet cable and powering it up. If you connect the wrong voltage, you may cause permanent electrical damage. Passive PoE is like plugging a 120V appliance into a 240V outlet, but with devices than cost much more than a simple toaster.


The big advantage of Power over Ethernet switch is that it allows greater flexibility in locating devices, as you don’t have to be situated near a power source—power is carried to them right in the Ethernet cable. That also frequently results in significantly lower installation costs, especially where many Access Points must be setup. The difference between Passive PoE and active PoE switch is quite obvious. For more, you can go through previous articles.


The ABCs of Tunable SFP+ & Tunable XFP DWDM Optics

Tunable XFP transceiver and tunable SFP+ transceiver are the hot-swap DWDM Tunable optics used in 10Gbps SONET/SDH, Fibre Channel and Gigabit Ethernet applications. Tunable DWDM transceiver is a unique device which allows customers to set the channel that the laser emits. Generally, the tunable optics is for C-Band 50GHz, starting from channel 16 up to 61 (depends on the manufacturer of the Router/Switch and which channels it supports). This article will shed light on the revolutionary Tunable DWDM transceivers.

Tunable Optics Gives You a lot of Flexibility

The introduction of these new optical components enable telecom, datacom, and enterprises operating a DWDM network to significantly reduce their sparing costs, improve their operational efficiencies, and turn up new customers or circuits in a fraction of the time it would normally take.

  • SFP+ Tunable Transceiver

10G DWDM tunable SFP+ transceiver is compliant to SFP+ MSA. This flexible transceiver can be tuned to any one of C-band channels with 50GHz spacing, supporting data rate of 10 Gbit/s-11.3 Gbit/s. DWDM tunable SFP+ transceiver operates over LC singlemode fiber for a max linking length of 80km.

Tunable SFP+ transceiver

  • XFP Tunable

Tunable XFP can be tuned from channel 1561.83 to 1530.33. This tunable optic has a reach of around 80km depending on the fiber quality and the mux type. The Cisco version is the “ONS-XC-10G-C” and there are more brands like Juniper, Ciena, Extreme and Brocade which are offering these optics.

Tunable Optics in DWDM networks

Typically, a DWDM network is set up with fixed wavelength DWDM transceivers. The laser hardware inside a DWDM optics has a fixed wavelength for transmitting over a DWDM channel. That means if one channel fails, you need this specific channel device in your spare part stock.

10G DWDM Tunable SFP+ & DWDM Tunable XFP+

A DWDM network can be used with 40 channels, so you need to stock 40 fixed wavelength DWDM modules. However, with Tunable SFP+ or XFP modules, you have the possibility to reduce OPEX or be flexible in terms of spare parts and stock.

To build a well-organized DWDM networks, you are supposed to scale up a wavelength planning for ordering the right types. There needs to be a documentation which specific channel is already in use at different locations. By the use of Tunable module, you just need to count the unused DWDM ports instead of each wavelengths and order the needed amount of only this one product. This reduces a lot of complexity and makes the planning so much easier.

Three Tips Before Using Tunable Optics

More expensive Than Fixed Wavelength DWDM Optics

Tunable transceivers renown as spare-optics, provide the flexibility to customers and reduce the amount of spare optics you need r to hold in stock. Owing to the special tunable laser in tunable optics, they are between two and four times more expensive than the regular static DWDM optics.

The following figure shows the cost comparison between DWDM SFP+ and Tunable SFP+ optics from FS.COM and Flexoptics.

DWDM SFP+ Vs Tunable SFP+

Some Switches/Routers Do Not Support CLI Command

In fact, the Tunable XFP/SFP+ can be tuned in different ways. It is such a new technology that currently, most high-end devices make it possible to tune over the command line interface, but not every switch or router is capable of this. For example the ASR9000 and the MX80 can be used for this but the EX4200 series from Juniper does not support this, which is indeed the biggest challenge in the tuning of these optics.

Not the mainstream in Metro & OTN Networks Now

Metro Ethernet network mainly consists of IP nodes, e.g. switches and routers interconnected by numbers of 10G interfaces. Network installers usually implement DWDM connectivity by using colored WDM transceivers in 10G ports and directly connect to dark fiber to line through passive optical multiplexer. According to the above description, only few of the IP node (optical switches and routers) support tuning wavelength of CLI commands.

And as for Optical Transport Networks (OTN), it is focusing on carrying payload and multiplexing, switching and supervising networks in optical Layer 1 domain. But how about tunable optical transceivers in OTN network..? Still, the mainstream is conventional fixed wavelength DWDM transceivers.

This compact device allows end-users to self-select any DWDM channel for each tunable SFP+ transceiver, tune it, and set it as a fixed-channel DWDM optic on demand. The whole DWDM sparing costs can be substantially reduced through the use of Tunable optics. Therefore, it would be popular in the near future.


In fiber optical networks where fixed DWDM channel XFP/SFP+ transceivers are currently used, changing to Tunable XFP/SFP+ transceivers offers the potential for large inventory stock reduction since all wavelengths can now be covered with one transceiver module. Tunable module will make itself a desirable choice to replace the fixed wavelength used in many networks.

10GBASE-T SFP+ Copper Module up to 200m – Is It Possible?

The introduction of 10gb SFP+ copper modules made people rethink 10G optical network, and was treated as the thrive of copper cabling. Vendors like Cisco, HPE, Amazon, prolabs and FS.COM provides 10GBase-T SFP+ module around $300 with 30m linking length and 2.5W power consumption, but it is a controversial and expensive copper devices. Today’s article decodes the 10GBASE-T SFP+ copper modules that can support up to 200m, and auto-negotiate to 1G, 2.5G, 5G data rate.

beautiful view

10GBASE-T Copper Can Auto-negotiate to 5G, 2.5G, 1G, 100Mbps, 10Mbps

10GBASE-T SFP+ transceivers, terminated with RJ45 connectors, allow 10G bandwidth over existing infrastructure and reuse Ethernet cables. However, owing to the high price and unstable performance, 10GBASE-T is not usually the type when competing with cost-effective DAC cables, and reliable SFP+ fiber modules. Customers use ideally DAC twinax cables for shorter reach transmission, or if they need longer distance, they would go for fiber SFP+ or SFP+ AOC cables.

10GBASE-T can auto-negotiate to 5G, 2.5G, 1G, 100Mbps, 10Mbps data rate, which is the highlight of this product. For 2.5GBASE-T/5GBASE-T networks, you can use this module.

Is It Possible to Support up to 200m?

The regular 10G copper modules launched by fiber optic vendors are specified to support up to 30m over Cat6a/Cat7 cables. According to wikipedia, 10GBASE-T, or IEEE 802.3an-2006 standard is released to provide 10G connections over unshielded or shielded twisted pair cables, with distances up to 100 meters (Cat6a), 55m (Cat6). What’s more, 10GBASE-T cable infrastructure can also be used for 1000BASE-T allowing a gradual upgrade from 1000BASE-T using auto-negotiation to select which speed to use.

Therefore, 10GBASE-T copper modules can auto-negotiate to lower data rate e.g. 10 Mbps, 100 Mbps, 1 Gbps, 2.5 Gbps, 5 Gbps, 10 Gbps. A new type 10GBASE-T SFP+ from Mikrotik can support all the above five data rates over different link length. The max power consumption is 2.4W, and can only be used in SFP+ ports.

Mikrotik 10Gig SFP+ copper

Table 2 shows the 10GBASE-T Cable Types and max supported lengths.

According to the above table, we can see that it can reach up to 200m over 1000BASE-T network, or at 2.5G 200m using Cat6a STP cables. So please be mindful of where you want to use them.

Isn’t 10GbE Copper Power Hungry?

10GBASE-Cu DAC twinax cables consumes 4-8 Watts power during the operation, while SFP+ 10GBASE-T copper modules draw less (2.5W), and it is not a standard compliant transceiver, hence the shorter distance of 30m. But if dig deeper, we will find that if there were more power, they would use it. So, in order to be fully compatible with 10GBASE-T standard, you need more power.

10GBASE-T SFP+ Module

Today’s fiber SFP+ modules like 10GBASE-SR draw less than 1W, much lower than the 5 to 8 Watts per 10GBASE-T port. Drawing an increase in power by a factor of 5 can seem like an expensive upgrade cost. When factored against servers that can draw up to 1000W or more, the overall proportion is low. For small to mid-sized (SMB) organization switch-server installations, short reach cable runs of less than 45 meters will apply and use even less power and therefore cost less.

Future-Proof 10GBase-T Technology

Although fiber becomes popular with the benefit of delivering flexible cabling, lowest latency, many IT departments still adopt copper cables for switch-to-switch or switch-to-server connections in 10G Ethernet applications. 10GBase-T Copper SFP+ is backward compatible with Fast Ethernet and Gigabit Ethernet and can automatically negotiate to lower speed connections. More importantly, 10GBase-T provides a cost-effective method for migrating from your current network to 10G Ethernet by utilizing your existing RJ-45 copper short connections. Amazon, FS.COM, Prolabs, Mikrotik and HPE supply 10GBAST-T copper transceivers, you can get what you want from them.

TP-Link 8-Port TL-SG1008D Desktop Switch

Ethernet switch usually acts as a hub that connects network devices and segments together while having the intelligence to send data where it needs to go. There are both managed and unmanaged switches. Managed switch as the names implies, can be programmed, while unmanaged switch simple allows Ethernet devices to communicate with one another. Besides, most fiber optic switches have 5, 8, 10, 24 or 48 ports. This article will introduce 5 TP-Link 8-Ports Desktop switch, and its cabling solutions.

8-Port Gigabit Desktop Switch TL-SG1008D

TL-SG1008D is the cost-effective TP-Link 8 port Desktop Gigabit Switch, which sells $24.99 . It has 8 Gigabit Auto-Negotiation RJ45 ports with switching capacity of 10Gbps. The TP-Link 8-Port desktop switch TL-SG1008D offer an easy path to make the transition to Gigabit Ethernet. Its auto-negotiation ports provide smart integration between 10Mbps, 100Mbps, and 1000Mbps hardware. With the innovative energy-efficient technology, the TL-SG1008D can save up to 75%/80% of the power consumption, making it an eco-friendly solution for your home or office network. Moreover, the auto features of TL-SG1008 unmanaged switch make installation plug and play and hassle-free.


    • Easy to Use

TL-SG1008 unmanaged switch has no need to configure. Once setting up in the office or home network, this optical switch will provide you with a high-performance, low-cost, easy-to-use, seamless and standard upgrade to 1000Mbps network. Simply plug and play, an ordinary person can install it. Moreover, auto MDI/MDIX eliminates the need for crossover cables.

    • High-Performance

All 8 ports of desktop switch, featuring non-blocking switching architecture can provide large file transferring and downloading that are compatible with 10Mbps and 100Mbps Ethernet devices. Supports IEEE 802.3x ow control for Full Duplex mode and back pressure for Half Duplex mode.

  • Power down Idle Ports

When a computer or network equipment is off, the corresponding port of a traditional switch will continue to consume considerable amounts of power. The TL-SG1008D can automatically detect the link status of each port and reduce the power consumption of ports that are idle, resulting in up to an 80% reduction in power use. Another great thing about this network switch is that it offers a fanless design, meaning that you won’t hear anything annoying while you are working.

Copper Cabling for Unmanged Switch TL-SG1008D

The TL-SG1008D Switch is equipped with 8 10/100/1000Mbps Auto-Sensing RJ45 ports that is aimed towards budget oriented people. For the price of TL-SG1008D, this low-priced fanless switch will take care of all your intermediate networking needs without a hiccup. Besides you can directly buy the cost-effective copper cables from FS.COM, which will surely save a large sum of money.

ID Cable Type Boot Type Conductor Type Jacket Length
13825 Cat5e UTP Snageless Booted
24AWG, Stranded Bare Copper


PVC 0.15-60m/Custom
22776 PVC
63764 Non Boot PVC
63634 Cat5e FTP Snageless Booted 26AWG, Stranded Bare Copper PVC
22346 Cat6 UTP Snageless Booted 24AWG, Stranded Bare Copper PVC
63088 LSZH
52067 Non Boot PVC
52173 Cat6 STP Snageless Booted 26AWG, Stranded Bare Copper PVC
23303 Cat6a STP Snageless Booted PVC 0.15-10m/Custom
23319 Snageless Booted LSZH
63503 Cat7 SSTP Snageless Booted 28AWG, Stranded Bare PVC 1-5m
63460 Slim Cat5e UTP Snageless Booted PVC
63118 Slim Cat6 UTP PVC

This is the simple layout of your network.

desktop Switch TL-SG1008D


Choosing the right optical switch is not an easy thing, either the experienced network installer, nor the completely inexperienced one. This article lists the main features of TL-SG1008D fanless switches, which will make sure people don’t have any issue choosing the best network switch in the market. Another great thing that we did to make things easier for you is making sure that you have abundance of options to choose from, from the highest end ones to the budget friendly ones, everything is basically in order for everyone.

Source: www.fiber-optic-solutions.com

Using Pre-terminated Cat6 Cable For Signal Extension

Thanks to the complexity of the fiber optic installation and audio video system, the need for sending multiple signal types and control over long distances has increasingly become intense. Ethernet cables like Cat 5e, Cat 6 and Cat 7, is an indispensable component for home or small business. Nowadays most manufacturers will recommend the use of solid shielded Cat 6 cable with shielded connectors other than using the HDBASE-T chipset for signal extension. This type of cable can be terminated in the field or purchased in specific lengths already terminated. The following article provides a brief introduction to the reasons why we should use Pre-terminated Cat 6 cables for the signal extension.

Cat6 Pre-terminated Trunk cable

Figure 1 shows the UTP Cat6 cables, Pre-terminated trunk cables, FS optical switches, cable manager wire duct.

Brief Outlook: Cat 6 Over Cat5 Cable

Cat5 and Cat6 copper Ethernet cables are the commonly used types for 1G/10G networks. So, what is the benefit of using Cat 6 cable instead of Cat 5?

In short, Cat 5e is a basic wire for home network. It is typically 24 gauge and can run 10 Gigabit network for 328 ft. While Cat 6 was developed to have 10 Gigabit networks. The only problem is that these wires were limited to a range of 164 feet. Above this, their speed will drop to 1Gbqs.

Besides distance and speed, Cat 6 patch cable also has another important difference, it has tighter twists in the cables. This allows each pair of wires to have two-way communication with each other. Cat 5e has an occasional delay and a higher skew than Cat 6 does. This means that even though Cat 5 can run at a speed of a Gigabit, it will appear to be slower.

Pre-terminated Solution that Saves Time, Money and Space

With connectors terminated on each end, Pre-terminated copper bundles provide a time saving and customized solution for reliable and easy to install connectivity. The Pre-terminated cables are made to your exact specifications, so there will be no unused cables left to be stored. No cable waste, faster turnaround and no terminating on site which means less money spent on storage, labor and equipment.

6 jack to 6 jack Cat6 cables

Figure 2 shows 6 Jack to 6 Jack Pre-terminated Copper Trunk Cable.

  • Flexibility, Efficiency and Reliability

The Pre-terminated Cat 6 copper bundles can be supplied in any length up to 60m and both ends have an installed Cat 6A modular jack (UTP). The cable bundle is held together with Velcro wraps at meter intervals and is generally supplied with 6 cables & installed jacks in a bundle. Each end of the Pre-terminated can be easily installed into an unloaded 19 rack mount patch panel, floor distributor or wall outlet.

  • Less labor intensive

Cat 6 Pre-terminated copper bundles require less work on site as no technical skills are needed when installing and connecting the cabling infrastructure. Therefore, this solution eliminates the need for technicians to be on site terminating cable, since the Pre-terminated cables can be easily installed by routing and then loading the Pre-terminated directly into a patch panel.

  • Less Wastage

The installer in a lot of cases has to pay for his waste to be removed from site on many projects, especially if they include cable drums, more importantly the installer is purchasing a more accurate quantity of cable, they are buying by the meter and not by the drum, how many installers have their facilities cluttered up with odd lengths of cables in boxes hoping for a project that will use them up.

Pre-Terminated Cable Limitations

  • Specialty cables must be planned for and ordered in advance
  • Inflexible in field run situations
  • Not feasible for retrofit and upgrade projects


Just as anything else, careful planning and product selection will be the key to a successful installation. You must consider resolution, distance, signal type or types, and physical layout when choosing a signal extension product. FS.COM Pre-terminated Cat 6 copper bundles offer rapid deployment coupled with guaranteed performance. Please feel free to contact us if you are interested.

Original Source : www.fiber-optic-solutions.com

How to Understand PoE and PoE+ Switches

Power-over-Ethernet (PoE) is the technology that allows network switches to transmit power and data through an Ethernet cable at the same time. PoE switch streamlines both of the processes of powering and providing data to the device, which makes it a straightforward and reliable device for home network and small enterprise application. This article describes two types of PoE (PoE and PoE+) that are commonly used and provides information on what types of PoE can be used according to different applications.

PoE Versus non-PoE Technology

Power over Ethernet technology facilitates powering a device (such as an IP phone, IP Surveillance Camera, or NVR recorder) over the same Ethernet cable as the data traffic. Figure 1 shows an Ethernet Network with IP camera, PoE Switch, NVR recorder and Wireless router. Compared to non-PoE devices, PoE devices feature with flexibility that allow you to easily place endpoints anywhere in the business, even places where it might be difficult to run a power outlet.

Wireless Home Network with POE switch

PoE Versus PoE+ Technology

PoE was first defined in the IEEE 802.3af standard. PoE devices utilize PoE standard, which can provide up to 15.4W of DC power to each port. A later standard, IEEE 802.3at, known as PoE+, increases the amount of power to 30 W. The major difference between 802.3af (PoE) and 802.3at (PoE+) is that PoE+ PSEs can provide almost twice as much power over a single Ethernet cable.

PoE and PoE+

Can PoE+ devices work over PoE Ports, Or vice versa? The PoE+ standard provides support for legacy PoE devices, meaning that an IEEE 802.3af powered device (PD) can operate normally when connected to IEEE 802.3at (PoE+) power sourcing equipment (PSE). PoE+ PSEs can supply power to both PoE and PoE+ PDs. However, as PoE+ PDs require more power than PoE PSEs can provide, PoE PSEs can only supply power to PoE PDs.

PoE Switch Or PoE+ Switch

Whether to use PoE or PoE+ switch for your network, you need to calculate your required power budget carefully for all of the PDs you plan to connect. PoE+ IEEE 802.3at devices can supply a maximum of 30 watts per port, while PoE IEEE 802.3af devices can supply a maximum of 15.4 watts per port. However, some power is always lost over the length of the cable, and more power is lost over longer cable runs. The minimum guaranteed power available at the PD is 12.95 watts per port for PoE and 25.5 watts per port for PoE+.

For most endpoints, 802.3af is sufficient but there are devices, such as Video phones or Access Points with multiple radios, which have higher power needs. It’s important to point out that there are other PoE standards currently being developed that will deliver even high levels of power for future applications. Optical switches have a power budget set aside for running the switch itself, and also an amount of power dedicated for PoE endpoints.

POE switch

FS PoE Switches

FS POE switches can supply power to network equipment such as weather-proof IP cameras, AP and IP telephones. They are featured with high flexibility, high stability and high resistance to electromagnetic interference. All FS PoE switches come with a one-year limited warranty, including any quality problems during the free maintenance. The following above shows 1G PoE Switch with 24 1000BASE-T and 4 SFP ports.

Original Source: How to Understand PoE and PoE+ Switches

What Are OM1, OM2, OM3 and OM4 Fiber Patch Cable?

Fiber optic cable can be divided into several types. Usually we see single-mode and multimode fiber types available on the market. Multimode fibers are described by their core and cladding diameters. The diameter of the multi-mode fiber is either 50/125 µm or 62.5/125 µm. At present, there are four commonly used OM (multimode) fibers: OM1, OM2, OM3 and OM4. Each type of them has different characteristics.

OM1 OM2 OM3 OM4 OM5 fiber cables

The picture above shows the development of OM multimode fibers. The Lime Green OM5 fibers are newly released and sure to be the mainstream transmission media in the near future. For more information about OM5 fibers, please turn to: OM5 Fiber Cable – Is It Worthwhile for 40G/100G SWDM4 Cabling Solution

OM Multimode Fiber Standard

Each “OM” has a minimum Modal Bandwidth (MBW) requirement. OM1, OM2, and OM3 are determined by the ISO 11801 standard, which is based on the modal bandwidth of the multi-mode fiber. In August of 2009, TIA/EIA approved and released 492AAAD, which defines the performance criteria for OM4. While they developed the original “OM” designations, IEC has not yet released an approved equivalent standard that will eventually be documented as fiber type A1a.3 in IEC 60793-2-10.

OM1, OM2, OM3 and OM4 multi-mode fiber

According to the above table,

  • OM1 cable typically comes with an orange jacket and has a core size of 62.5 micrometers (µm). It can support 10 Gigabit Ethernet at lengths up 33 meters. It is most commonly used for 100 Megabit Ethernet applications
  • OM2 also has a suggested jacket color of orange. Its core size is 50µm instead of 62.5µm. It supports 10 Gigabit Ethernet at lengths up to 82 meters but is more commonly used for 1 Gigabit Ethernet applications.
  • OM3 has a suggested jacket color of aqua. Like OM2, its core size is 50µm. OM3 supports 10 Gigabit Ethernet at lengths up to 300 meters. Besides OM3 is able to support 40 Gigabit and 100 Gigabit Ethernet up to 100 meters. 10 Gigabit Ethernet is its most common use.
  • OM4 also has a suggested jacket color of aqua. It is a further improvement to OM3. It also uses a 50µm core but it supports 10 Gigabit Ethernet at lengths up 550 meters and it supports 100 Gigabit Ethernet at lengths up to 150 meters.

OM1 Vs. OM2 Vs. OM3 Vs. OM4 Fiber

There are several differences between four kinds of multi-mode fiber, and we can see them clearly from the table below:

OM1, OM2, OM3 and OM4 multi-mode fiber

  • Diameter: The core diameter of OM1 is 62.5 µm , however, core diameter of the OM2, OM3 and OM4 is 50 µm.
  • Jacket Color: OM1 and OM2 MMF are generally defined by an orange jacket. OM3 and OM4 are usually defined with an aqua jacket.
  • Optical Source: OM1 and OM2 commonly use LED light source. However, OM3 and OM4 usually use 850 nm VCSELs.
  • Bandwidth: At 850 nm the minimal modal bandwidth of OM1 is 200MHz*km, of OM2 is 500MHz*km, of OM3 is 2000MHz*km, of OM4 is 4700MHz*km.

Why Are OM3 & OM4 Fiber Superior to OM1 & OM2?

10G OM3Both OM1 and OM2 work with LED based equipment that can send hundreds of modes of light down the cable, while OM3 and OM4 fiber are optimized for laser (eg. VCSEL) based equipment that uses fewer modes of light. LEDs can not be turned on/off fast enough to support higher bandwidth applications, while VCSELs are capable of modulation over 10 Gbit/s and are used in many high speed networks. For this reason, OM3 and OM4 are the multimode fibers included in the 40G and 100G Ethernet standard. Now OM1 and OM2 are usually used for 1G which are not suitable for today’s higher-speed networks. OM3 and OM4 are used for 10G mostly at present. But in the future, since OM3 and OM4 can support the 40G and 100G, which may make them the tendency.

Original Source: www.fiber-optic-solutions.com/what-are-om1-om2-om3-and-om4.html