ARRL Technician Practice Exam

Which of the following would be connected between a transceiver and computer in a packet radio station?

1. Audio interface

2. Terminal node controller

3. RF amplifier

4. Microphone preamp

The correct answer is: Terminal node controller

In a packet radio station, connecting a terminal node controller (TNC) between a transceiver and a computer is essential for digital communication. The terminal node controller serves as an interface that translates digital data from the computer into audio tones suitable for transmission via the radio and also converts incoming audio signals back into digital data for the computer. The TNC modulates the digital signals from the computer into audio signals that can be sent over the radio waves. It performs the necessary processing to ensure that the data can be transmitted reliably, enabling data packets to be sent and received effectively. This is critical in packet radio operations, where digital communication over radio frequencies is the primary purpose. While options like an audio interface, RF amplifier, and microphone preamp serve important functions in different contexts, they do not specifically handle the digital-to-audio modulation required in a packet radio setup. An audio interface generally deals with sound signals, an RF amplifier boosts radio frequency signals for transmission, and a microphone preamp enhances the signal from a microphone—all of which are not directly suited for the digital packet communications that the TNC facilitates.