What are Shielded Ethernet Cables?
Currently, the use of high bandwidth applications has been on the rise, and network systems have started venturing into factory environments which have called for the use of shielded cables. In this new installation sector, the cable is used in areas with high electromagnetic interference (EMI). Even with improved ability to reject noise and handle gigabit Ethernet, these cables will not function properly in areas where there is high EMI if not properly shielded. A shielded cable will help in these high EMI installations ensuring safe and efficient data transfer.
STP and S/STP
These are the two basic types of shielded ethernet cables. STP cables with an overall generic shield whereas S/STP cables have a shield for each pair and an overall outer shield. The Shield of STP cables can either be a foil or a braid, but for additional strength, some cables can comprise of a foil shield and an outer braid shield.
STP and FTP
Cables which have an overall foil are known as FTP, whereas those with a braid are known as STP. STP is the generic name given to all shielded cables. At times, there arises confusion where FTP cables are assumed to be unshielded or that they are significantly different in terms of performance. In practice, the STP and FTP cables can be used interchangeably, and there is no apparent difference in their performance.
The second type of cable is one that has each of the individual pair shielded and then there is an overall outer shield. This type of cable is referred to as S/STP. The purpose of having an inner shield is to ensure that there is no internal cross-talk between the pairs. This will help in ensuring that the cables meet the specifications of the Alien Cross Talk parameter which is significantly difficult to achieve with CAT6a and CAT7 systems. However, Alien Cross Talk is not a requirement when it comes to CAT6, CAT5e, and CATS systems. Additionally, it does not significantly contribute to the overall resilience of the cable when it comes to resisting external RF noise such as the one made at the mains induced spikes. The physical construction comprises of a foil on both the inner and overall outer shield. Additionally, there can be a braid which will improve the cables strength and also simplify the connection to the metal shields which are around the connectors.
Proper Ground Connection
It is worth noting that all the shielded Ethernet cables should have a ground connection for their shields. In case your cable has an incorrect ground connection, the chances are there will be ground loop currents and also the associated interference to the Ethernet signal. In the worst case scenario, where the grounding is poor, the shield can end up acting like antennas; broadcasting high-frequency signals from the cable to the outer environment. This will interfere with the delicate co-located electronic equipment and also allow external detection of the Ethernet data.
What is the Drain Wire in Shielded Cables?
Every shielded Ethernet cable should have a wire that stretches from the insulated wires to the shield. This is commonly known as the drain wire. Normally, the shield is connected to a specific pin in one end, which can even be the chassis. The connector shells are not connected anywhere and consequently, connecting the drain wire to pin 1 puts the entire cable at the potential of that pin. No current will be flowing, but the cable screening will be effective.
Bottom line on Shielded Patch Cables
Ethernet cables should be shielded which helps increase the cables resilience and also makes it stronger. As such, when going for Ethernet cables, consider going for ones which are shielded to ensure safety and longevity.
Additional Ethernet Resources
- The Right Ethernet Cables for High Density Networks
- What are Ferrari-style Ethernet Cables?
- What is the difference between Cat5e, Cat6, and Cat6a?
- What is Cat8 and how is it different from other Ethernet cables?
- Ethernet for Challenging Installs
- Shop all CablesAndKits Ethernet Cables
- Visit the CK Learning Center