1.25G SFP Transceiver Solution

SFP optical module is a compact optical transceiver module used in communication field. SFP optical transceivers are designed to support SONET/SDH, Fast Ethernet, Gigabit Ethernet, Fibre Channel and other communications standards. It interfaces a network device motherboard (switch, router, media converter or similar device) to a Fiber Channel or Gigabit Ethernet optical fiber cable at the other end. SFP transceivers are available in a wide range of data rates including 155M, 622M, 1.25G and 2.5G, which allows users to choose the most suitable transceiver for each link. Today’s article will illustrate the most popular 1.25G SFP transceivers.

Description of SFP Transceiver

SFP modules can be divided into different types according to different standard. Here is what you need to know about SFP modules. The transmission distance of a SFP is up to 120km for single-mode and 2km for multimode fiber. The SFP fiber transceiver could be dual fibers with LC connectors, or single fiber with LC or SC connectors. The wavelengths could be 850nm, 1310nm and 1550nm. The 1.25G SFP optical transceiver modules are available in different standard such as 1000BASE-T, 1000BASE-SX, 1000BASE-LX/LH, etc. The following part explains such types.

1000BASE-SX SFP Transceiver

1000BASE-SX SFP transceiver is a cost effective 850nm module supporting dual data-rate of 1.25Gbps/1.0625Gbps. It is compatible with the IEEE 802.3z 1000BASE-SX standard and operates multimode fibers link up to 550 m. The fiber optic transceiver consists of three sections: a VCSEL laser transmitter, a PIN photodiode integrated with a trans-impedance preamplifier (TIA) and MCU control unit. This SFP type (e.g. J4858B) is usually applied for Fiber Channel links, Gigabit Ethernet links, Fast Ethernet links, etc. J4858B (see in Figure 1) is HP 1000BASE-SX SFP that is widely welcomed by overall users.

1000BASE-LX/LH SFP Transceiver

1000BASE-LX/LH SFP transceiver is a high performance 1310nm transceiver for single-mode fibers. It is compatible with the IEEE 802.3z 1000BASE-LX standard and also supports dual data-rate of 1.25 Gbps/1.0625 Gbps with a transmission distance of 10 /15 /20 km. Cisco GLC-LX-SM-RGD (shown in Figure 2) is 1000BASE-LX/LH SFP that can operate on standard single-mode fiber-optic link spans of up to 10 km and up to 550 m on any multimode fibers. HP J4860C is a 1000BASE-LH SFP that can operates over 1550nm for a distance of 70km. Unlike Cisco GLC-LX-SM-RGD SFP, J4860C can support a much longer distance of 70km, which is ideal for long-haul network application.

10/100/1000BASE-T SFP Transceiver

10/100/1000BASE-T SFP Transceiver is compatible with the Gigabit Ethernet standard as specified in IEEE STD 802.3. It supports data rates of 10/100/1000 Mbps, fully satisfying 10/100/10001000BASE-T applications such as LAN 10/100/1000Base-T Fiber Channel links, Gigabit Ethernet over Cat 5 Cable, Switch to Switch Interface, Router/Server interface, etc.

Why Choose Compatible SFP Module

We have introduced several SFP modules above including the HP SFPs. The original SFP optical transceivers are very expensive, the simple solution to this is to find a reliable OEM vendor. Besides saving cost, there are many others reasons that you should choose to purchase a compatible SFP, SFP+ or XFP fiber optic transceiver. For example in a scenario where gigabit speed is required to run across a point-to-point link, the distance between the link length is assessed and an appropriate SFP transceiver module native to the host device is chosen. If a HP platform was in situation, then the selection of module will be limited by among the following: 550 meter (J4858B), 10km (J4859B), 40km (JD061A) or the maximum 70km (J4860C). Using a compatible SFP you can choose from a variety of distance limits from 550meters up to 100km in numerous increments with distances of 160km being achievable on the top product lines.

Another advantage of use compatible SFP transceivers is the freedom to tailor the transceiver to your individual requirement. Custom serial numbers can be added both to the product label and also hard coded to the device itself. Latches can be color coded for high density link identification Fiberstore also provide a recoding service in China, this specific service means existing SFP's can be adapted if the host device is to be changed. In some instances, even cross-device compatibility is quite possible.

Conclusion

Because of its high performance and small size, SFP transceiver replaces the former GBIC module and becomes the most used fiber optic transceiver module in the telecommunication industry. Currently, many optical vendors supply optical transceiver modules. Fiberstore, as a professional telecom manufacturer and supplier, offers a full range of SFP optical transceivers that are 100% compatible with large brands. We are committed to provide high-quality products and long-term customer services to our customers. Any interested in our products, you can contact us directly.

1000BASE-SX SFP Transceivers for Gigabit Ethernet

Standardized by the IEEE, Gigabit Ethernet is a term describing various technologies for transmitting Ethernet frames at a rate of a Gigabit per second, which has been considered to be a viable solution for increased bandwidth requirements for growing networks. 1000BASE SFP transceiver is a hot-pluggable input/output device that plugs into a Gigabit Ethernet port/slot, linking the port with the network. Recently the market is flooded with various 1000BASE SFP transceivers available for Gigabit Ethernet. With so many options out there in the market, people may feel puzzled about how to select the one that is in in accordance with their application. Therefore the following article will make a brief introduction to the 1000BASE SFP to help you choose the most suitable one.

Fiber-based or Copper-based Gigabit Ethernet

According to cable material, Gigabit Ethernet can be classified into fiber-based Gigabit Ethernet and copper-based Gigabit Ethernet. In fiber-based Gigabit Ethernet, 1000BASE-X is used to refer to Gigabit Ethernet transmission over fiber. 1000BASE-X is a group of standards for Ethernet physical layer standards. These standards include: 1000BASE-SX (A fiber optic Gigabit Ethernet standard for operation over multi-mode fiber), 1000BASE-LX (a fiber optic Gigabit Ethernet standard using a long wavelength laser and a maximum RMS spectral width of 4 nm), 1000BASE-LX10 (which is very similar to 1000BASE-LX, but achieves longer distances over a pair of single-mode fiber), 1000BASE-BX10 (which is capable of up to 10 km over a single strand of single-mode fiber) or the non-standard 1000BASE-EX ( a industry accepted term to refer to Gigabit Ethernet transmission) and 1000BASE-ZX (a multi-vendor term to refer to Gigabit Ethernet transmission) implementations.

While for copper-based Gigabit Ethernet, 1000BASE-CX, 1000BASE-KX, 1000BASE-T and 1000BASE-TX are four standards for Gigabit Ethernet over copper wiring. 1000BASE-CX uses copper cables as a medium. 1000BASE-KX is part of the IEEE 802.3ap standard for Ethernet Operation over Electrical Backplanes. 1000Base-T uses four pairs of Category 5 unshielded twisted pair cables to achieve Gigabit data rates. 1000BASE-TX is similar to 1000BASE-T but uses two pairs of wires rather than four for data transmission.

1000BASE SFP Transceivers for Gigabit Ethernet

1000BASE SFP transceiver is a device that interfaces a network device motherboard to a fiber optic or copper networking cable. It is designed to support Gigabit Ethernet, Fibre Channel and other communications standards. As noted before, there are 1000BASE optical SFP transceivers and 1000BASE copper SFP transceivers used in Gigabit Ethernet. The following part will go on to talk about one of the 1000BASE optical SFP transceivers—1000BASE-SX SFP.

The 1000BASE-SX is one of the physical layer standards for Gigabit Ethernet, meaning the single optic fiber 1000Mbps baseband transmission standard. “S” refers to short-range multimode optical cable, while “X” means 4B/5B block coding for Fast Ethernet or 8B/10B block coding for Gigabit Ethernet. The standard specifies a transmission distance between 220 m and 550 m. It is highly popular for intra-building links in large office buildings, co-location facilities and carrier neutral internet exchanges. Therefore, 1000BASE-SX SFP transceiver module is the best seller in those fields.

Two 1000BASE-SX SFP Transceivers

The 1000BASE-SX SFP transceiver module is compatible with the 1000BASE-SX standard. It can support up to 1km over laser-optimized 50μm multimode fiber cable. The wavelength range that 1000BASE-SX SFP transceiver module transmits and receives is from 770nm to 860nm. Fiberstore provides a variety of 1000BASE-SX SFP transceivers that are fully compatible with other brands. Take AA1419048-E6 and TL-SM311LM as an example.

AA1419048-E6AA1419048-E6 is Avaya Nortel 1000BASE-SX SFP transceiver module for multimode fiber. It is the multimode module with a wavelength of 850nm. Avaya Nortel 1000BASE-SX SFP transceiver module supports hot-pluggable SFP footprint duplex LC connector Interface. This transceiver is built to comply with Multi-Source Agreement (MSA) standards. AA1419048-E6 supports dual data-rate of 1.25Gbps/1.0625Gbps, which is widely used in fiber channel links, Gigabit Ethernet links, Fast Ethernet links, other optical links.

TL-SM311LMBesides AA1419048-E6, TL-SM311LM from TP-LINK is also available in the market for supporting Gigabit Ethernet Application. TL-SM311LM has the same specification with other 1000BASE-SX SFPs, which supports a link length of up to 550m on multimode fiber.

As there are different physical layer standards for Gigabit Ethernet, different 1000BASE SFP transceivers may be used for different application. These 1000BASE SFP transceivers can be used for single-mode and multimode fibers of different reaches. 1000BASE-SX SFP transceiver can operate link spans of up to 550m on any multimode fibers. Fiberstore produces a variety of compatible 1000BASE SFP with high quality and low prize including the above two SFP transceivers. We can also customize optic transceiver to meet your specific requirements. If you have any interest, please send your request to us.

Dig Deeper Into SFP Transceivers

Small form-factor pluggable (SFP) is a prevailing type of optical transceivers in the market widely utilized for Gigabit Ethernet application. As it has the same function with GBIC but with a smaller size, SFP transceiver is also called mini-GBIC. Optical transceivers are typically designed to both transmit and receive electrical optical signals under the Multi-Source Agreement. Each SFP module can support data rates from 1Gbps to 10Gbps. And there are a number of SFP modules and network accessories available for you to select from. Which one suits you better? The following article will dig deeper into the SFP transceivers that will help decide which one will work best for you.

SFP transceivers have a variety of different transmission and receiving type, users can select the appropriate transceiver for each link, to provide the optical performance can be achieved based on the available fiber type (such as a multimode fiber or single-mode fiber). Optical SFP modules available are generally divided into the following categories. Figure 1 displays the basic components of a SFP transceiver.

 

1000BASE-LX—Specified in IEEE 802.3 Clause 38, 1000BASE-LX uses a long wavelength laser (1270-1355 nm), and a maximum RMS spectral width of 4nm. 1000BASE-LX is designed to cover a distance of up to 10 km over 10µm single-mode fiber. 1000BASE-LX can also run over all common types of multimode fiber with a maximum segment length of 550 m. For link distances greater than 300 m, the use of a special launch conditioning patch cord may be required. E1MG-LX-OM is Brocade 1000BASE-LX SFP that can work over a distance of 10km.

1000BASE-EX—1000BASE-EX is not a standard but industry accepted term for Gigabit Ethernet transmission. It is very similar to 1000BASE-LX10 but achieves longer distances up to 40 km over a pair of single-mode fibers due to higher quality optics than a LX10, running on 1310nm wavelength lasers. It is sometimes referred to as LH (Long Haul).

1000BASE-ZX—1000BASE-ZX is also a non-standard but multi-vendor term using 1,550nm wavelength to achieve distances of at least 70 kilometers over single-mode fiber. Some vendors can specify distances up to 120 kilometers over single-mode fiber. Ranges beyond 80 km are highly dependent upon the path loss of the fiber in use, specifically the attenuation figure in dB per km, the number and quality of connectors/patch panels and splices located between transceivers.

1000BASE-SX—1000BASE-SX is a Gigabit Ethernet standard for operation over multimode fiber using a 770 to 860 nm, near infrared (NIR) light wavelength for a maximum of 550m at 1.25 Gbit/s (gigabit Ethernet) or 150m at 4.25 Gbit/s (Fibre Channel). Take EX-SFP-1GE-SX as an example, it is 1000BASE-SX SFP that can support a link length of 550m over OM2 cable. Figure 2 shows that EX-SFP-1GE-SX inserts into a Juniper SRX210.

 

1000BASE-BX10—1000BASE-BX10 is capable of up to 10 km over a single strand of single-mode fiber, with a different wavelength going in each direction. The terminals on each side of the fiber are not equal, as the one transmitting downstream uses the 1490nm wavelength, and the one transmitting upstream uses the 1310nm wavelength.

1000BASE-T—It is a standard for Gigabit Ethernet copper cabling. The maximum length of 1000GBASE-T is 100 meters. 1000BASE-T must use Category 5 cable or better (including Cat 5e and Cat 6. 1000BASE-T can be used in data centers for server switching, for uplinks from desktop computer switches, or directly to the desktop for broadband applications.

1000BASE-TX—Created by the Telecommunications Industry Association (TIA), 1000BASE-TX (TIA/EIA-854) is a standard similar to 1000BASE-T that was simpler to implement. Compared with 1000BASE-T, this simplified design would have reduced the cost of the required electronics by only using two unidirectional pairs in each direction instead of 4 bidirectional. However, this solution has not been widely used largely due to the required Category 6 cabling and the rapidly falling cost of 1000BASE-T products.

Recommended Information It is known that there is no visual difference between the bare SFP modules, so how to differ them? Smart manufacturers figure a way out by marking the color of pull ring to distinguish generally. For example: black pull ring is multimode, the wavelength is 850 nm; blue is the 1310nm module; yellow is the 1550nm module; purple is the 1490nm module and so on. If you are confused with the specifications of the SFP modules, you should find a reliable vendor to help you. Fiberstore provides a variety of SFP modules including 100BASE SFP, 1000BASE SFP, BiDi SFP, CWDM/DWDM SFP, SONET/SDH SFP and 2G/4G FC SFP. Our SFP modules are fully compatible with major brand. For more information about SFP transceivers, please feel free to contact us.

The Basics of 1000BASE-SX and 1000BASE-LX SFP

Gigabit Ethernet has been regarded as a huge breakthrough of telecom industry by offering speeds of up to 100Mbps. Gigabit Ethernet is a standard for transmitting Ethernet frames at a rate of a gigabit per second. There are five physical layer standards for Gigabit Ethernet using optical fiber (1000BASE-X), twisted pair cable (1000BASE-T), or shielded balanced copper cable (1000BASE-CX). 1000BASE-LX and 1000BASE-SX SFP are two common types of optical transceiver modules in the market. Today’s topic will be a brief introduction to 1000BASE-LX and 1000BASE-SX SFP transceivers.

1000BASE in these terms refers to a Gigabit Ethernet connection that uses the unfiltered cable for transmission. “X” means 4B/5B block coding for Fast Ethernet or 8B/10B block coding for Gigabit Ethernet. “L” means long-range single- or multi-mode optical cable (100 m to 10 km). “S” means short-range multi-mode optical cable (less than 100 m).

1000BASE-SX
1000BASE-SX is a fiber optic Gigabit Ethernet standard for operation over multi-mode fiber using a 770 to 860 nanometer, near infrared (NIR) light wavelength. The standard specifies a distance capability between 220 meters and 550 meters. In practice, with good quality fiber, optics, and terminations, 1000BASE-SX will usually work over significantly longer distances. This standard is highly popular for intra-building links in large office buildings, co-location facilities and carrier neutral internet exchanges. 1000BASE-SX SFP works at 850nm wavelength and used only for the purposed of the multimode optical fiber with an LC connector. 1000BASE-SX SFP traditional 50 microns of multimode optical fiber link is 550 meters high and 62.5 micron fiber distributed data interface (FDDI) multimode optical fiber is up to 220 meters. Take EX-SFP-1GE-SX as an example, its maximum distance is 550m with DOM support. The 1000Base-SX standard supports the multimode fiber distances shown in table 1.

1000BASE-LX
Specified in IEEE 802.3 Clause 38, 1000BASE-LX is a type of standard for implementing Gigabit Ethernet networks. The "LX" in 1000BASE-LX stands for long wavelength, indicating that this version of Gigabit Ethernet is intended for use with long-wavelength transmissions (1270–1355 nm) over long cable runs of fiber optic cabling. 1000BASE-LX can run over both single mode fiber and multimode fiber with a distance of up to 5 km and 550 m, respectively. For link distances greater than 300 m, the use of a special launch conditioning patch cord may be required. 1000BASE-LX is intended mainly for connecting high-speed hubs, Ethernet switches, and routers together in different wiring closets or buildings using long cabling runs, and developed to support longer-length multimode building fiber backbones and single-mode campus backbones. E1MG-LX-OM is Brocade 1000BASE-LX SFP that operates over a wavelength of 1310nm for 10 km.

Difference Between LX, LH and LX/LH
Many vendors use both LH and LX/LH for certain SFP modules, this SFP type is similar with the other SFPs in basic working principle and size. However, LH and LX/LH aren’t a Gigabit Ethernet standard and are compatible with 1000BASE-LX standard. 1000BASE-LH SFP operates a distance up to 70km over single-mode fiber. For example, Cisco MGBLH1 1000BASE-LH SFP covers a link length of 40km that make itself perfect for long-reach application. 1000BASE-LX/LH SFP can operate on standard single-mode fiber-optic link spans of up to 10 km and up to 550 m on any multimode fibers. In addition, when used over legacy multimode fiber type, the transmitter should be coupled through a mode conditioning patch cable.

Conclusion
1000BASE SFP transceiver is the most commonly used component for Gigabit Ethernet application. With so many types available in the market, careful notice should be given to the range of differences, both in distance and price of multimode and single-mode fiber optics. Fiberstore offers a large amount of in-stock 1000BASE SFP transceivers which are compatible for Cisco, Juniper, Dell, Finisar, Brocade, or Netgear in various options. If you have any requirement of our products, please send your request to us.

The Evolution Path of BASE-T

With the requirements laid on data center increasing rapidly, the ability to flexibly adapt to future demands is tremendously crucial for data center managers. Often this can be achieved by deploying higher bandwidth solutions in a part of the data center, provided that these systems are backwards compatible with existing infrastructure or it may be a cost-consuming method. BASE-T technology featured by its low cost, availability and flexibility is largely favored by data center designers. This article illustrates the migration of BASE-T technology so that people can future proof their data center tomorrow.

Why BASE-T Is so Popular?
To be short, three main advantages will be concluded in the following part.
1. Least cost access layer alternative when compared to other interconnect technologies

• Optical (e.g. SR, LR)
• Direct-Attached

2.Structured topology

• Common physical interface (RJ45)
• Flexibility and longevity
• Optimized for small to medium-sized data centers (< 20K square feet)

3. Supports auto-negotiation and Power-Over-Ethernet

• Simple plug and play installation
• Ubiquitous RJ45 interface simplifies 10GBASE-T to 40GBASE-T upgrade path

1000BASE-T—Gigabit Ethernet Over 4-pair Cat 5 Cabling
1000BASE-T (ratified in 1999) is a Gigabit Ethernet standard over copper wiring at the speed of 1000 Mbps. Each 1000BASE-T network segment can support a maximum length of 100 meters, and uses Category 5 cable or better (including Cat 5e and Cat 6). 1000BASE-T also uses a symbol rate of 125 Mbaud and all four pairs for the link and a more sophisticated five-level coding scheme. The 1000BASE-T SFP operates on standard Category 5 unshielded twisted-pair copper cabling of link lengths up to 100 m.

Realizing 10BASE-T
Upgraded from 1000BASE-T, 10GBASE-T (certificated in 2006) offers the most flexibility, the lowest cost media, and is backward-compatible with existing 1 GbE networks. 10GBASE-T connected with Cat 6 and Cat 6A (or above) cabling supports a length up to 100 meters that gives IT managers a far greater level of flexibility in connecting devices in the data center. 10GBASE-T and Category 6A cabling costs less than using either optical fiber or SFP+ direct attach copper (DAC) options that have been widely deployed to date center for 10 Gb/s. For example, EX-SFP-10GE-DAC-1M can only support a link length of 1m that largely limits its application. Figure 1 presents a comparison between 1000GBASE-T and 10GBASE-T.

Road to 40GBASE-T in Data Center Networks
If there is a 10GBASE-T for switch-to-server and switch-to-switch connectivity, there will be a 40GBASE-T over twisted pair cabling for the 40G data center deployment according to the IEEE. Twisted pair cabling with the RJ-45 connector has always been the first choice for IT professionals, based on its low cost and ease of use. Unlike fiber or twinax solutions, twisted pair cabling can automatically switch to different data rates, such as from 100MbE to 10GbE. Therefore migration to 40GBASE-T does not require a upgrade of all the equipment of the data center, which will reduce of the overall expenditure of the data center.

The advantages of 40GBASE-T are clear, but the path from initial ratification to commercial availability is not always smooth. There still a few months off for 40GBASE-T standardization, here comes some good news, as well as some considerations.

40GBASE-T is specified with transmission performance up to 2 GHz (four times the bandwidth of Category 6A) with a lot more stringent alien crosstalk requirements. Since initial 40GBASE-T applications would be limited to data centers, the traditional twisted pair Ethernet 100m link length is not essential. Additionally, Industry players helping in the development of an industry standard for 40GBASE-T have to ensure that it could be supported and rolled out cost-effectively. The new standard will minimize the time it will take to develop new electronics for switches and servers that can support 40GBASE-T connectivity, by building on the work already completed to support 10GbE connections. The standard will also support the ubiquitous RJ-45 connector. Sooner or later, 40GBASE-T will be upon us. Nowadays 40GBASE-LR4, 40GBASE-SR and 40G QSFP+ cables are there to help with the deployment of 40G connectivity. Take JG330A as an example, it is QSFP+ to 4SFP+ Passive Copper Cable available for short reach application. Figure 2 shows a data center twisted-pair migration roadmap.

Summary
BASE-T technology (1000BASE-T, 10GBASE-T or 40GBASE-T) always retains the traditional advantages—low cost, easy to deploy and auto-negotiation for plug and play and backwards compatibility. 1000BASE-T and 10GBASE-T have already brought benefits to people. But no one can foresee that 40GBASE-T will be used in the future but future-proof planning of the cabling is important, given the long life of the cabling systems. Fiberstore provides a full range of BASE-T products including 1000BASE-T SFP, 1000BASE-T media converter, 1000BASE-T GBIC transceiver, etc. And 40GBASE-T devices will be coming soon. If you have any request of our products, please send your inquiry to us.

1000BASE-T – Gigabit Over Copper Cabling

With the massive applications of bandwidth-related products in telecommunication networks, people may encounter a dilemma of whether to deploy fiber-based or copper-based infrastructure. Limited budget always comes as an essential factor deciding people’s choice, under this circumstance, copper cabling or 1000BASE-T proves to be a nice and cost-saving method.

What Does 1000BASE-T Mean?
1000Base-T is a shorthand designation by the Institute of Electrical and Electronics Engineers (IEEE). The 1,000 refers to the transmission speed of 1,000 Mbps, while “base” refers to baseband signaling, which means that only Ethernet signals are being carried on this medium. The “T” refers to the twisted pair cables this technology uses. The following image shows a compatible Finisar FCLF8521P2BTL.

1000Base-T is a type of gigabit Ethernet networking technology that uses copper cables as a medium. 1000Base-T uses four pairs of Category 5 unshielded twisted pair cables to achieve gigabit data rates. The standard is designated as IEEE 802.3ab and allows 1 Gbps data transfer for distances of up to 330 feet.

Comparison Between 100BASE-TX, 1000BASE-X, and 1000BASE-T
1000BASE-T is one of the four physical layers or transceivers defined by the two Gigabit Ethernet standards: IEEE 802.3z or 1000BASE-X and IEEE 802.3ab or 1000BASE-T. The following text will describe the comparison between 100BASE-TX, 1000BASE-X, and 1000BASE-T in details. Firstly, let us see the table below.

1000BASE-X supports multi-mode and single-mode fiber media and a short-reach, 25-meter copper jumper. As most of the cabling installed inside buildings today is Category 5 copper, the IEEE 802.3 1000BASE-T standard supports Gigabit Ethernet operation over the Category 5 cabling systems installed according to the specifications of ANSI/TIA/EIA-568A (1995). 1000BASE-T, however, works by using all four of the Category 5 pairs to achieve 1000 Mbps operation over the installed Category 5 copper cabling. 1000 Mbps data rates are achieved by sending and receiving a 250 Mbps data stream over each of the four pairs simultaneously.

In contrast, 100BASE-TX uses two pairs: one to transmit and one to receive. Fast Ethernet on Copper (100BASE-TX) achieves 100 Mbps operation by sending encoded symbols across the link at a symbol rate of 125 Mbaud. A 125 Mbaud symbol rate is required because the 100BASE-TX encoding scheme (called 4B/5B coding) has a bandwidth overhead of 20 percent, the difference between 100 Mbps and 125 Mbaud. Although 1000BASE-T uses a different encoding scheme (five level pulse amplitude modulation or PAM-5), because it maintains the 125 Mbaud symbol rate of 100BASE-TX, 1000BASE-T is backwards compatible with 100BASE-FX at the physical layer.

This compatibility feature is significant for network managers and planners because it means that forthcoming generations of 1000BASE-T NICs and switches will support both 100/1000 and 10/100/1000 autonegotiation between Fast Ethernet (100BASE-TX) and Gigabit Ethernet (1000BASE-T). These speed-agile products will enable network managers to deploy 1000BASE-T incrementally into the network.

Fiberstore Compatible 1000BASE-T Transceiver
1000BASE-T is a time-saving and cost-effective solution. Various products have been provided to enhance the 1000BASE-T performances. Fiberstore provides a wide range of 1000BASE-T transceiver modules including FCLF8521P2BTL, AA1419043-E6 and SFP-1GE-FE-E-T. Please feel free to contact us for more information about 1000BASE-T transceivers.

Reference:
http://www.cisco.com/c/en/us/products/collateral/interfaces-modules/gigabit-ethernet-gbic-sfp-modules/product_data_sheet0900aecd8033f885.html