Tag Archive for Cat 5e

| January 12, 2019
Comments Off on Why Shielded Cables?

Why Shielded Cables?

Why Shielded Cables?With high bandwidth applications emerging in and out of the data center, the need for shielded cable has increased. Many of these new installations are in harsh environments.  Robotic equipment, motors, generators, air conditioners, fluorescent lights, printers, and they often generate a large amount of EMI (Electromagnetic Interference) and RFI (Radio Frequency Interference). You may need to install shielded cables in these harsh environments.

interference will cause increased errorsEMI and RFI can cause crosstalk between circuits and interfere with data transmission on a copper cable. The interference will cause increased errors resulting in mire network traffic due to packet retransmissions, and downtime.

Shielded cables reduce interfernece

EMI is an unwanted signal that is induced into the cable. EMI typically comes from a source that is external to the cable, such as an electrical cable or device. Cables can be both a source and receiver of EMI. As a source, the cable can either conduct noise to other equipment or act as an antenna radiating noise. As a receiver, the cable can pick up EMI radiated from other sources.

RFI is a disturbance that affects an electrical circuit due to either electromagnetic conduction or radiation emitted from an external source. Conducted RFI is unwanted high frequencies that ride on the AC waveform. Radiated RFI is emitted through the air.

Ethernet cables can be shielded to deal with EMI and RFI.  The shield surrounds the inner signal carrying conductors. Shielded Ethernet cables can deal with interference in two ways. It can reflect the energy, or it can pick up the interference and conduct it to ground. Both methods use shielding to cut the EMI and RFI reaching the twisted pairs located under the shielding. Whether the EMI/RFI is reflected off the shield or “rides” the shield to ground, some energy can still pass through the shielding, but since it is so highly attenuated it will not cause interference.

Types of shielded cables

Two basic types of shielded cables are available. The first are cables with an overall shield known generically as STP. STP cable may be made either with a foil or a braid for the shield. STP cables with an overall foil are often known as FTP. In practice, FTP and STP cables may be interchanged with no apparent difference in performance according to BlackBox

Cable types
The second type of shielded cable is S/STP. S/STP cables have a shield around each individual pair and an overall outer shield. BlackBox says the purpose of the inner shields is to cut the Alien Cross Talk parameter in CAT7 and CAT6a systems.On both STP and S/STP the primary task of the outer shield is to resist external RF noise such as electrical spikes.  S/STP cables may also have an extra braid for strength and to simplify connection to the metal shields around the connectors.
Cable constructionTo reduce EMI/RFI interference, shielded Ethernet cables must use shielded connectors to maintain the benefits of STP cabling. High-quality shielded cable includes a drain wire to provide grounding that cancels the effects of EMI and can ease termination of the cable shield for crimping or soldering.

Redi WattProper Ground connections

The shielded cable system must have proper ground connections for the shields. Incorrect grounding opens the possibility for ground loop currents and associated interference to the Ethernet signal. In the worst cases with no proper grounding, the shields can actually act as antenna broadcasting high-frequency signals out into the environment interfering with electronic equipment and allowing external detection of the Ethernet data.

Standards bodies have requirements for shielded Ethernet systems. The American National Standards Institute (ANSI) specifics how shielded communications cables are properly grounded. Normal practice says the cable shields should be grounded in the telecommunications closet (TC). Typically, the cable shield is grounded through the connector to the patch panel. Then the panel is grounded to the rack, which is grounded to the telecommunications grounding busbar in the TC. Do not ground the cable shield at the work-area outlet. Fortunately, many of today’s shielded outlets automatically connect to the patch panel’s ground so there’s no need to set up ground paths for each cable.

ISO/IEC requires that shielding must be complete for an entire channel, shielded and shielded cables, connectors or network controllers should not be mixed.

Cable Types

Category cable types comparison.
Max Data RateMax TX RateMax LengthSheildingYear IntroducedStatus
Cat 310Mbps16MHz100mNo1983Obsolete
Cat 5 1,000Mbps100MHz100mOptional1995Obsolete
Cat 5e1,000Mbps250MHz100mOptional2001Obsolete
Cat 6 10,000Mbps500MHz100mOptional2002
Cat 6a10,000Mbps500MHz100mOptional2008
Cat 7 10,000Mbps600MHz100mRequired2002Not recognized by TIA
Cat 7a10,000Mbps1GHz100mRequired2010Not recognized by TIA
Cat 8.140,000Mbps2GHz30mRequired2016Backward compatible with Cat 6A
Cat 8.240,000Mbps2GHz30mRequired2016Not recognized by TIA

rb-

interference is not a new problem. It dates back to the earliest communication systems. In 1881 Alexander Graham described the interaction between many twisted pairs in US Patent 244,426.

Related articles

 

Ralph Bach has been in IT long enough to know better and has blogged from his Bach Seat about IT, careers, and anything else that catches his attention since 2005. You can follow him on LinkedIn, Facebook, and Twitter. Email the Bach Seat here.

Category: Uncategorized | Tags: , , , , , , , , , , , ,
| November 17, 2015
Comments Off on Sun Setting on Cat 5e

Sun Setting on Cat 5e

Sun Setting on Cat 5eThe sun is setting on the Cat 5e cabling standard. The long-standing standard defined how most commercial spaces around the world were cabled for nearly 20 years. Starting in 2017 Cat 5e will be considered obsolete for new installations following a decision by the ISO/IEC cabling standards body.

recommendation for Category 6AIn a recent blog post at CommScope (COMM), the ISO cabling standards body JTC1/SC25 WG3 working group agreed to raise the minimum horizontal cabling requirement. The new standard is stated in ISO/IEC 11801-2. Office space requirements change from Class D (Category 5e) to Class E (Category 6). It includes a recommendation for Class EA (Category 6A). Cat 6A will enable a smooth migration to 2.5, 5, and ultimately 10 gigabits per second (Gbps). In the drafts of 11801-5 (data centers) and 11801-6 (distributed services), the minimum requirement is already Class EA cabling.

Ethernet and IP communications everywhere

The original ISO/IEC 11801 standard enabled the explosive growth and mass deployment of Ethernet and IP communications everywhere. In its first edition, the author says the standard defined Class D balanced cabling based on Category 5 copper components. This standard offered an upgrade path from 10 to 100 megabits per second (Mbps) up to 100 meters. At that time, some experts and industry observers argued that 100 Mbps (100BASE-T) to the desk was overkill for the typical office user.

handful of cablesToday, 100BASE-T technology is in a rapid market decline. 100BASE-T is being replaced with 1000BASE-T (1 Gbps) according to the article. 1000BASE-T is commonplace for desktop and laptop PCs. It also benefits a wide range of other devices such as phones, cameras, and wireless access points (WAPs).

The 11801 standard now includes more cabling classes that were introduced to enable support of up to 10 Gbps. The new classes include Class E (Category 6), Class F (Category 7). Even more recently, Class EA (Category 6A) and Class FA (Category 7A).

Technology trends

According to the CommScope blog, a number of technology trends made ISO choose to upgrade the minimum recommendation for horizontal cabling in offices. Some of the trends recognized by the committee that are driving the adoption of speeds beyond one Captain Ethernetgigabit on the horizontal cabling include:

The rapid growth of BYOD is driving infrastructure upgrades to accommodate IEEE 802.11ac. As I have covered before, new IEEE specifications are being developed to accommodate 802.11ac wireless. 2.5GBASE-T is targeted at installed Class D cabling and 5GBASE-T is targeted at installed Class E cabling. It is expected that a sizable percentage of the installed base will be able to support the faster speeds, however, some installed Class D and Class E systems may require some mitigation steps.

Related articles

 

Ralph Bach has been in IT long enough to know better and has blogged from his Bach Seat about IT, careers, and anything else that catches his attention since 2005. You can follow him on LinkedIn, Facebook, and Twitter. Email the Bach Seat here.

Category: Uncategorized | Tags: , , , , , , , , , , , , , , , , , , ,
| April 27, 2007
Comments Off on Low Voltage Cable Costs Rising

Low Voltage Cable Costs Rising

Updated – 03-05-08 – Military tensions in South America are driving the costs of copper and oil up even more.

Low Voltage Cable Costs RisingLast year, there was a large jump in copper telecom cable costs as manufacturers passed along raw material price increases in copper and petroleum. These price increases have affected all wire and cable products including plenum and non-plenum products; Cat 3, Cat 5e, Cat 6, Cat 6a, multi-pair cables, outside plant cables, and all low voltage electronic wire. Despite a market correction at the end of 2006, copper and petroleum prices used to manufacture cable are headed up again-meaning copper telecom cable will be following suit soon.

[Most Recent Quotes from www.kitco.com]The fundamental cause for increasing copper telecom cables is the continuing global demand for copper and petroleum. China and Asia lead the demand for Copper. The U.S. demand is for copper is down due to the collapsing housing market, however, if the U.S. housing market ever takes off again, more demand pressure will drive copper prices higher.

China which is the world’s largest consumer of copper accounting for 20% of the world’s supply imported 61% more copper in March 2007 than in March of 2006. The U.S. consumes 13% of the world’s copper. Demand for copper has reduced the worldwide supply of available copper to less than four days of global use.

[Most Recent Quotes from www.kitco.com]The upward pressure on copper telecom cables will follow technological globalization. The per capita demand for copper rises as GDP per capita rises. BaseMetals.com indicates that Japan consumes around 12kg per capita, North America consumers around 10kg per capita, and Europe around 9kg per capita. The large populations of China, India, Eastern Europe and South America are consuming less than 2kg per capita.

WTI crude oil pricesIn addition to copper price pressure, the cost of oil also impacts telecom cable prices. George Bush’s war in Iraq and declining world oil production have led to price increases in gasoline and petrochemicals such as PVC resins and polyethylene which are derivatives of crude oil and used in the manufacture of telecom cables. Escalating crude oil prices have also increased transportation costs leading to increased freight charges and other transportation costs across the value chain.

The dual price pressures of copper and petroleum will continue to push up the cost of all cabling.

Related articles
  • BT denies it is sitting on a ‘copper mine’ worth £50bn (telegraph.co.uk)

Ralph Bach has been in IT long enough to know better and has blogged from his Bach Seat about IT, careers, and anything else that catches his attention since 2005. You can follow him on LinkedIn, Facebook, and Twitter. Email the Bach Seat here.

Category: low voltage | Tags: , , , , , , ,