Which cable type includes a foil shield and a drain wire?

Which cable type includes a foil shield and a drain wire?

• A. UTP
• B. ScTP
• C. STP
• D. STP-A

Answer: (B)

Shielding in twisted-pair cables relies on a barrier to block interference and a grounded conductor to carry that shield to ground. A foil shield provides the barrier, and the drain wire gives a low-impedance path to ground so the shield stays bonded and effective. This combination—foil shield plus a drain wire—is characteristic of Screened Twisted Pair. Unshielded twisted pair has no shielding, while STP variants may use a braided shield and don’t necessarily rely on a foil with a drain wire. STP-A isn’t the standard foil-with-drain-wire arrangement. So the foil shield with a drain wire best identifies Screened Twisted Pair.

Shielding in twisted-pair cables relies on a barrier to block interference and a grounded conductor to carry that shield to ground. A foil shield provides the barrier, and the drain wire gives a low-impedance path to ground so the shield stays bonded and effective. This combination—foil shield plus a drain wire—is characteristic of Screened Twisted Pair. Unshielded twisted pair has no shielding, while STP variants may use a braided shield and don’t necessarily rely on a foil with a drain wire. STP-A isn’t the standard foil-with-drain-wire arrangement. So the foil shield with a drain wire best identifies Screened Twisted Pair.