A Copper-based Gigabit Ethernet Solution – 1000BASE-T

Enormous efforts put on the development of high-performance Ethernet technology that provides gigabit-per-second transmission rates have led to the extension of Gigabit products to include the copper Gigabit Ethernet (GbE) standard: 1000BASE-T. Many papers and articles have been attributed to introducing the fiber-optic GbE standards, such as 1000BASE-SX, 1000BASE-LX, 1000BASE-ZX. And contributions are few about 1000BASE-T. This text just helps you to better understand 1000BASE-T and talks about it: a copper GbE solution.

What Is 1000BASE-T Technology?

1000BASE-T is also known as IEEE 802.3ab. Just judging from its name, “1000” here means the transmission speed of 1000Mbps. The “BASE” refers to BASE band signaling, indicating that only Ethernet signals are carried on the medium. The “T” represents twisted-pair copper cable (for example Cat 5). More specifically, 1000BASE-T uses four pairs of Cat 5 unshielded twisted pair (UTP) to achieve the Gigabit data rate and achieves 1000Mbps data rates by sending and receiving a 250Mbps data stream over each of the four pairs simultaneously. The distribution of four-pair Cat 5 cabling extends from the work area to the equipment room and between equipment in the equipment room, thus enabling connectivity to switched and shared gigabit services for both high-bandwidth work area computing and server farms.

four cat 5 UTP pairs

1000BASE-T is able to provide half-duplex (CSMA/CD) and full-duplex 1000Mb/s Ethernet service over Cat 5 links as defined by ANSI/TIA/EIA-568-A. Besides GbE applications over Cat 5 copper cabling, 1000BASE-T also supports other specifications. First, it supports the Ethernet MAC (Media Access Control), and is backward compatible with a 10/100 Mbps Ethernet. Second, many 1000BASE-T products support 100/1000 auto-negotiation, and therefore 1000BASE-T can be incrementally deployed in a Fast Ethernet network. Third, 1000BASE-T is a high-performing technology with less than one erroneous bit in 10 billion transmitted bits. (10 is the same error rate as that of 100BASE-T.) Topology rules for 1000BASE-T are the same as those used for 100BASE-T.

Why Choose This Copper Gigabit Ethernet Solution?

Why network designers choose 1000BASE-T as the copper GbE solutions? Or put it in another way, what are the advantages of 1000BASE-T?

  • Performance—1000BASE-T scales Ethernet 10/100Mbps performance to 1000Mbps. Compared with 1Gbps, 1000BASE-T is 100 times as fast as the standard Ethernet. It permits the smooth migration of the 10/100 networks to 1000 Mbps-based networks. When 1000BASE-T technology is deployed in transceiver modules, these 1000BASE-T copper SFP transceivers, such as Fiberstore compatible Cisco SFP-GE-T, make shared gigabit service possible and aggregate one gigabit of server support. This Cisco 1000BASE-T SFP supports 1000BASE-T operation in host systems with a compact RJ-45 connector assembly.

SFP-GE-T, Cisco 1000BASE-T SFP

  • Cost—Used in conjunction with Full Duplex Repeaters (FDRs), 1000BASE-T can provide highly cost-effective shared gigabit service. FDRs offer the traditional low-cost shared media operation of repeaters, but when coupled with 1000BASE-T, they offer an easy-to-manage, high-burst rate, shared-media solution capable of supporting both end users and server farms. In such a case, to aggregate one gigabit of server support is possible in a cost-effective way.
Notes on Using 1000BASE-T Products

While realizing a 1000Mb/s data stream over four pairs of Category 5 twisted pair cables meet several challenges may meet several challenges, like signal attenuation, echo, return loss, etc.

  • Attenuation is the signal loss of the cabling from the transmitter to the receiver. Attenuation increases with frequency, so designers are challenged to use the lowest possible frequency range that is consistent with the required data rate.
  • Echo is a by-product of dual-duplex operation, where both the transmit and receive signal occupy the same wire pair. The residual transmitted signal because of the trans-hybrid loss combines with the cabling return loss to produce an unwanted signal referred to here as echo.
  • Return loss is a measure of the amount of power reflected due to cabling impedance mismatches.

1000BASE-T technology is the ideal high-speed solution for these application when 1000BASE-T uplinks from desktop switches to aggregating switches. Many network designers have chosen this copper GbE solution for high network performance in a cost-effective way. Fiberstore supplies many 1000BASE-T SFPs which are fully compatible with major brands, like Cisco GLC-T and SFP-GE-T mentioned above. For more information about 1000BASE-T SFPs, you can visit Fiberstore.

Related Article: A Quick Overview of Cisco 1000BASE-T GLC-T SFP Copper Module

CAT5 – Copper Network Solutions Choice

Defined by the Electronic Industries Association and Telecommunications Industry Association (commonly known as EIA/TIA), CAT5 (Category 5) cable is the copper wiring using twisted pair technology, designed for Ethernet networks. The term “Category” refers to the classifications of UTP (unshielded twisted pair) cables. Since its inception in the 1990s, CAT5 has become one of the most popular types of of all twisted pair cable types which include CAT3, CAT4, CAT5, CAT6, etc. This article details CAT5 used in copper networks from its working principles, its standard, as well as its installation considerations.

How CAT5 Cable Technology Works

CAT5 is widely used in 100BASE-TX and 1000BASE-T Ethernet networks. CAT5 typically contains four pairs of copper wire. In 100BASE-TX standard, the signals are transmitted across only two of the CAT5 pairs. One pair is used to transmit signals, and the second pair receives the signals, leaving the other two unused in signal transmission. What’s more, the 100BASE-TX signals only run in one direction across the pairs. As technology advanced, the 1000BASE-T Gigabit Ethernet (GbE) standard was developed. 1000BASE-T standard utilizes all four copper pairs to transmit up to 250 megabits of data per second (Mbps) in full duplex transmission across each pair. That is to say, each pair is able to transmit and receive signals simultaneously. 1000BASE-T modules (eg. GLC-T) functioning over CAT 5 with RJ-45 connector achieve full duplex transmission with link length up to 100m (328ft).

GLC-T, functions over CAT 5 with RJ-45 connector

There are two standards for CAT5 wiring, EIA/TIA-568A and EIA/TIA-568B. The following passages mainly discuss EIA/TIA-568A.


The TIA-EIA-568-A standard defined the following three main parameters for testing Category 5 cabling installations: wiremap, attenuation, and Near End Crosstalk (NEXT).

Wiremap is a continuity test. It assures that the conductors that make up the four twisted pairs in the cable are continuous from the termination point of one end of the link to the other. This test assures that the conductors are terminated correctly at each end and that none of the conductor pairs are crossed or short-circuited.

Attenuation is the loss of signal, as it is transmitted from the end of the cable to the opposite end at which it is received. Attenuation, also referred to as Insertion Loss, is measured in decibels (dB). For attenuation, the lower the dB value is, the better the performance is, and of course less signal is lost. This attenuation is typically caused by absorption, reflection, diffusion, scattering, deflection.

Near End Crosstalk (NEXT) measures the amount of signal coupled from one pair to another within the cable caused by radiation emission at the transmitting end.If the crosstalk is great enough, it will interfere with signals received across the circuit. Crosstalk is measured in dB. The higher the dB value, the better the performance, more of the signal is transmitted and less is lost due to coupling.

NEXT: the amount of signal coupled from one pair to another

CAT5 Installation Considerations

After testing parameters are mentioned above, here goes the notes of CAT 5 installation.

  • Never pull CAT5 copper wire with excessive force. The CAT5 tension limitation is 25 lbs, much lower than standard audio/video cable.
  • Never step on, crush, or crimp CAT5.
  • Avoid periodic sags; vary the intervals if the cable must sag.
  • Do not bend CAT5 wire tightly around a corner; ensure that it bends gradually, so that a whole circle would be at least two inches in diameter.
  • Do not allow knots or kinks, even temporarily.
  • Never run CAT5 parallel to power wiring closer than six inches.
  • Avoid splices. Every splice degrades the line.

Although CAT5 is superseded by CAT5e in many applications, most CAT5 cable meets Cat5e standards and it’s still a commonplace in Local Area Networks (LANs). Many copper networks choose CAT5 as their transmission media because of its low price and high performance. Fiberstore supplies many CAT5 RJ45 pluggable modules, like 100BASE-TX, and 1000BASE-T transceivers (eg. SFP-GE-T). For more information about copper network solutions, you can visit Fiberstore.