Final answer:
The PSTN is a circuit-switched network that uses traditional copper wires to transmit voice signals.
Step-by-step explanation:
The Public Switched Telephone Network (PSTN) is a circuit-switched network. In a circuit-switched network, a dedicated communication path is established between two parties for the duration of their conversation. The PSTN uses traditional copper wires to transmit voice signals, making it a circuit-switched network.