What is the primary difference between STP and UTP cables?

The primary difference between STP (Shielded Twisted Pair) cables and UTP (Unshielded Twisted Pair) cables lies in their construction and the presence of shielding. STP cables have an additional layer of shielding around the twisted pairs of wires. This shielding helps protect the data signals from external electromagnetic interference, which can be a significant factor in environments with a lot of electronic noise. The shielding enhances the cable's ability to maintain signal integrity, especially over longer distances or in situations with considerable interference.

On the other hand, UTP cables do not have this outer shielding, making them generally more susceptible to external noise and interference. While they can be effective for many networking applications, they may not perform as well as STP cables in challenging environments. Therefore, the correct answer accurately identifies that STP has outer shielding, while UTP does not, highlighting a fundamental aspect of these two types of cabling used in networking.