What type of channel setup uses one frequency for transmitting and a second frequency for receiving?

The scenario described pertains to a communication method that utilizes two distinct frequencies—one designated for transmitting data and another for receiving it. This setup is characteristic of a duplex communication system.

Duplex communication allows for simultaneous two-way communication, facilitating more efficient transmission of information. In situations where separate frequencies are employed for sending and receiving signals, both parties can communicate without interference, improving clarity and reducing delays. This is particularly advantageous in firefighting scenarios where timely and clear communication can be critical for operations and safety.

In contrast, simplex communication uses a single frequency dedicated to one-way transmission only, which limits interaction. Half-duplex allows for two-way communication but only one direction at a time, implying that while one party transmits, the other has to wait before responding. Full-duplex, though it may seem similar to duplex, often suggests simultaneous transmission and reception on the same frequency, which is not the case here. Therefore, the correct choice indicates a system designed for effective two-way communication using separate frequencies for each function.