ARRL Technician Practice Exam

What type of communication involves two stations transmitting and receiving on different frequencies?

1. Simplex communication

2. Duplex communication

3. Half-duplex communication

4. All of the above

The correct answer is: Duplex communication

Duplex communication is characterized by the ability for two stations to send and receive signals simultaneously, but on different frequencies. This method allows for a continuous flow of communication, enabling each station to transmit while still being able to receive incoming transmissions without interference. In contrast, simplex communication allows for communication in only one direction at any given time, where one station transmits and the other listens, but not simultaneously. Half-duplex communication permits two-way communication but only one station can transmit at a time—this means that while one station is sending a message, the other must wait to respond. Given the nature of duplex communication, where both stations operate on different frequencies and can communicate concurrently, it is the appropriate choice for this question.