Tag: Alien crosstalk

Tightly bundled or combed UTP Cables increase risk of Alien Crosstalk

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Whenever Category 6A UTP cables capable of supporting 10 Gig applications are combed or tightly bundled, you risk increased alien crosstalk (AXT) that can wreak havoc on high speed transmission. Why? Alien crosstalk is caused by interference on a cable pair from a pair in an adjacent cable, and it became an issue with Category 6A cabling characterized up to 500 MHz simply due to the higher level of frequency and noise. So it’s easy to understand that anytime cables are evenly combed or tightly bundled together so that they lay adjacent to one another, alien crosstalk will increase—precisely why worst-case alien crosstalk testing involves six around one.

All About Alien Crosstalk Measurement

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Alien crosstalk is the coupling of noise from one cable link to another. This happens if one cable is surrounded by many other cables in a bundle. We identify the cables that surround a cable in a bundle as Disturbers. Cables that can suffer from noise coupling from other cables are identified as the Disturbed cable or (Victim).This becomes more important as we increase the bandwidth requirement of cables for faster applications and the surrounding cables (Disturbers) impact the ability of the disturbed cable (Victim) to transmit data.  You might think that using shielded cables i.e. (where there is at least an outer shield) then alien crosstalk would not be a problem. However, if the shield is not terminated correctly even a shielded system can fall foul of alien crosstalk.