Screened Twisted-Pair (ScTP) cable provides very good rejection of which type of interference?

Screened Twisted-Pair (ScTP) cable provides very good rejection of which type of interference?

• A. Low-frequency electrical interference
• B. Thermal noise
• C. High-frequency electrical interference
• D. DC offset

Answer: (C)

Shielded Twisted-Pair provides strong rejection of external electromagnetic interference, especially at high frequencies. The metallic shield around the conductors acts like a Faraday cage, blocking much of the ambient RF noise from reaching the signal-carrying wires. This shielding is most effective for high-frequency interference because rapid voltage changes from RF sources induce currents that the shield can easily divert to ground, keeping the signal lines cleaner. The twisted-pair itself helps by differential signaling, which cancels noise that appears equally on both conductors, and shielding adds another layer of protection by reducing how much external fields couple into the pair in the first place. Noise caused by thermal agitation (thermal noise) or a DC offset comes from the electronics or resistive elements, not from external RF interference, so shielding doesn’t eliminate those. For best results, the shield must be properly grounded and continuous; gaps or poor grounding can reduce its effectiveness.

Shielded Twisted-Pair provides strong rejection of external electromagnetic interference, especially at high frequencies. The metallic shield around the conductors acts like a Faraday cage, blocking much of the ambient RF noise from reaching the signal-carrying wires. This shielding is most effective for high-frequency interference because rapid voltage changes from RF sources induce currents that the shield can easily divert to ground, keeping the signal lines cleaner. The twisted-pair itself helps by differential signaling, which cancels noise that appears equally on both conductors, and shielding adds another layer of protection by reducing how much external fields couple into the pair in the first place. Noise caused by thermal agitation (thermal noise) or a DC offset comes from the electronics or resistive elements, not from external RF interference, so shielding doesn’t eliminate those. For best results, the shield must be properly grounded and continuous; gaps or poor grounding can reduce its effectiveness.