Tag Archive for Cat 5

| January 12, 2019
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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

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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.

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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: , , , , , , , , , , , ,
| February 26, 2013
Comments Off on Cables Carrying Fake UL Marks

Cables Carrying Fake UL Marks

Cables Carrying Fake UL MarksUnderwriters Laboratories recently warned that two communications cable products carried “counterfeit UL marks.” Neither cable has been evaluated by the laboratory for safety. In addition, UL claims that the two cables do not contain required flame-retardant elements, so they both pose fire hazards. The first warning regards a StarTech product while the second carries the brand name Monoprice.

StarTech communications cableBack in January Underwriters Laboratories (UL) issued a public notice that identified StarTech communications cable as being mislabeled. According to an article in Cabling Installation & Maintenance, UL stated that the cable, “bears a counterfeit UL Mark for the United States and may pose a fire hazard.” The safety organization states, “The communications cable has not been evaluated by UL to the appropriate standard for safety in the United States, and is not authorized to bear the UL mark or any reference to UL.”

Further, the notice states that the cable “is missing required flame retardant elements. This may cause an increased risk of fire.” The box bears the brand name StarTech and has the terms “ISO 9011,” “UL,” “ETL,” and “IECQ” printed on it. According to UL’s notice, the cable jacket includes the following: “CMR Type 4PR 24AWG 75C (UL) E151955-A CSA LL79189 ETL Verified TIA/EIA-568-B.2 CAT 5E UTP 350 MHZ Patch Cable B-8A1004 ROHS Compliant.” The UL alert says that the cable was sold at overstock.com and may have been sold at other locations.

In a February article at Cabling Installation & Maintenance, there is a similar problem with cable sold by Monoprice. The UL issued, an alert to the public that Monoprice cable uses the UL mark without authorization and lacks certain fire-retardant materials. The UL alert says this cable is known to be also sold at www.greenconnectionsusa.com

The Fiber Optic Association has a YouTube video that demonstrates the fire dangers of counterfeit communications cable.

The StarTech response to the UL warning shared with Cabling Installation & Maintenance seemed more concerned about their ISO certification than correcting the problem. StarTech issued the following statement on January 24: “StarTech.com has been an ISO 9001 registered company since 1998 and is currently certified as ISO 9001:2008 compliant. As such, we take this matter seriously and have issued an internal corrective action report (CAR) and are investigating the circumstances surrounding this incident. Based on the outcome of our investigation, appropriate action will be taken.”

Unbeknownst to usMonoprice’s response to Cabling Installation & Maintenance came from company rep. Chris Apland. The firm claimed they did not know about the misleading and dangerous cat 5 cables. He claims they did not know what their vendor was doing. “Unbeknownst to us at the time, Monoprice’s former vendor for the product in question was inappropriately labeling our product certifications.”

He goes on to claim the firm is sorry and has changed its ways. “Monoprice terminated our relationship with the vendor in question … We apologize to both UL and to our customers for any confusion this may have caused.” Mr. Apland added in the firm’s response that Monoprice’s “new vendor provides a higher quality Cat 6 bulk cable that includes the critical fire-retardant material called for in the UL complaint … we have since been in contact with UL through our China office…”

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In order to prevent safety problems on your job site, the Communications Cable and Connectivity Association (CCCA) recommends the best practice is to buy proven quality, name-brand cables and patch cords for known vendors.

Other recommendations include:

  1. Check for the UL holographic label on all boxes or reels of cable.
  2. Verify the UL mark and cable type on the cable jacket.
  3. Consult the UL online certifications directory to find if the manufacturer has a UL listing via the UL file number (the E number).
  4. Verify the authorized UL marks and correct terminology appear in cable specifications (cut sheets)
  5. Weigh the box of cable. Substantially less weight may indicate non-compliant copper clad aluminum (CCA) conductors were used in place of solid copper

The CCCA has developed the Cable Check™ App to help check these best practices. Download the app from Apple’s (AAPL) iTunes to detect cables carrying fake UL marks on your job.

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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: , , , , , , , ,
| 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.

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  • 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: , , , , , , ,