CompTIA Network+ Practice Test

What is a significant characteristic of twisted pair copper cables?

1. They contain only one wire

2. They utilize a single twist rate

3. They have equal and opposite signals in pairs

4. They are always shielded for protection

The correct answer is: They have equal and opposite signals in pairs

Twisted pair copper cables are notably characterized by having equal and opposite signals in each pair of wires. This design helps to reduce electromagnetic interference and crosstalk from outside sources as well as from adjacent pairs within the same cable. By twisting the wires together, the electrical fields produced by the signals in the wires effectively cancel each other out when they are equal and opposite. This dual-signal approach enhances the integrity and quality of data transmission over longer distances, making twisted pair cables a common choice for networking. The other characteristics presented do not accurately reflect the nature of twisted pair cables. For instance, having only one wire is not a feature of twisted pair cables since they are composed of pairs. Utilizing a single twist rate is misleading; twisted pairs can have varying twist rates depending on the cable specification and the application, which can also contribute to performance differences. While some twisted pair cables may be shielded, not all of them are, as unshielded twisted pair (UTP) cable is a prevalent type used in many networking scenarios. Therefore, the defining characteristic revolves around the equal and opposite signal design.