Optimizing Performance: Shielded Twisted Pair (STP) and EMI Management

The Shielded Twisted Pair (STP) solution is the second most deployed in the market, with the Unshielded Twisted Pair (UTP) solution being the first. STP is employed in industries with equipment that can produce higher electromagnetic interference (EMI) or noise, which can impact the performance of copper cables. Therefore, STP provides protection to ensure the performance of the copper cable.

What Is STP Solution?

The STP solution includes shielded copper horizontal cable, shielded jack module, shielded panel, and shielded patch cord. Proper bonding and grounding are essential for the complete connectivity solution to dissipate EMI through the shielded solution to the earth for neutralization.

Figure 1. Shielded Solution Categories Naming

STP is categorized based on the construction of the shielding. In Figure 1, the first word before the slash denotes the overall cable shielding after the jacket, and the second word after the slash refers to the twisted pair shielding.

1. S/FTP or Braided Shield over Foil Shield Twisted Pair
2. F/FTP or Foil Shield over Foil Shield Twisted Pair
3. F/UTP or Foil shielded over Unshielded Twisted Pair

Figure 2. STP categories quality from high to low

There are other STP categories, including SF/UTP and U/FTP. If you are interested in shielded solutions, please check out this Shielded Solution Catalogue. Figure 2 indicates the quality of the shielded categories from the highest to the lowest immunity to EMI.

Where Is STP Solution Mainly Used?

Figure 3. Industries that may require STP solution

In most deployments today, shielded solutions are not commonly required, such as in data centers and commercial buildings. However, industries that may still necessitate shielded solutions include manufacturing facilities and hospitals, as depicted in Figure 3, where EMI interference could be high and potentially cause network disruption. Before Cat6A technology, shielded solutions were the primary options, addressing not only EMI but also alien crosstalk interference.

Shielding Category: Which Should You Choose?

As mentioned in the previous topic, the common STP categories used in today’s market are mainly S/FTP, F/FTP, and F/UTP. In fact, F/FTP solution deployment has been rarely seen compared to 10 years ago. The reason is that most equipment today produces lesser EMI interference due to technological advancement. Based on the quality of shielding, the recommended approach is deploying S/FTP for horizontal (permanent link) cable connections and F/UTP for patch cord connections. This is because horizontal connections can go through pathways that are susceptible to EMI interference, while front patching is minimal.

How To Deploy A Complete STP Solution

Figure 4: STP standard solution deployment

A complete STP solution comprises cable, jack module, panel, and patch cord that are in the STP category, and it requires a proper bonding and grounding system. Failure to comply results in a broken STP solution that doesn't work. This means you would be paying big bucks for a substandard solution, equivalent to a UTP solution. Figure 4 indicates a properly deployed STP solution.