Polarity in copper cabling testing refers to the correct orientation of the pairs; incorrect polarity can cause what?

• A. Improper signaling
• B. Improved shielding
• C. Reduced physical size
• D. Increased data rate

Answer: (A)

Polarity testing checks that each wire in a twisted pair is oriented the same way on both ends so the differential signal is interpreted correctly. The signal on a pair is the difference between the two conductors; if you swap the two wires in a pair, you flip the polarity. While many modern Ethernet receivers can tolerate a polarity reversal, some equipment or legacy configurations can misinterpret that signal, leading to errors or “improper signaling.” That’s why ensuring proper polarity is important in copper cabling tests. The other options don’t fit because shielding, physical size, and the data rate are not determined by which conductor is considered the positive or negative wire, but by the cable design and standard itself.