What signals are used in a computer-radio interface for digital mode operation?
The correct answer is C: Receive audio, transmit audio, and transmitter keying. In a computer-radio interface for digital mode operation, the key signals are receive audio (from radio to computer), transmit audio (from computer to radio), and transmitter keying (PTT control from computer to radio).
Digital modes require the computer to receive audio from the radio (to decode received signals), send audio to the radio (to transmit encoded signals), and control when the radio transmits (PTT/keying). Some interfaces also provide CAT (Computer Aided Transceiver) control for frequency and mode control, but the three essential signals are audio in, audio out, and PTT. These three connections allow full digital mode operation.
Exam Tip
Digital interface = Audio in, audio out, PTT. Remember: A computer-radio interface for digital modes needs receive audio, transmit audio, and transmitter keying (PTT). These are the three essential signals.
Memory Aid
"**D**igital **I**nterface = **A**udio **I**n, **A**udio **O**ut, **P**TT (think 'DI = AIAOP')"
Real-World Application
You're setting up a digital mode interface between your computer and transceiver. You connect: (1) transceiver audio output to computer audio input (receive audio), (2) computer audio output to transceiver microphone input (transmit audio), and (3) computer PTT control to transceiver PTT input (keying). With these three connections, your computer can decode received digital signals and encode/transmit digital signals.
FCC Part 97.3Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Receive/transmit mode, status, and location are CAT control functions, not the essential audio/keying signals needed for digital operation.
Option B: Incorrect. Antenna and RF power aren't part of the computer interface. These are separate from the audio/keying interface.
Option D: Incorrect. NMEA GPS and DC power aren't part of the digital mode interface. GPS might be used separately, but it's not essential for the computer-radio interface.
题目解析
The correct answer is C: Receive audio, transmit audio, and transmitter keying. In a computer-radio interface for digital mode operation, the key signals are receive audio (from radio to computer), transmit audio (from computer to radio), and transmitter keying (PTT control from computer to radio). Digital modes require the computer to receive audio from the radio (to decode received signals), send audio to the radio (to transmit encoded signals), and control when the radio transmits (PTT/keying). Some interfaces also provide CAT (Computer Aided Transceiver) control for frequency and mode control, but the three essential signals are audio in, audio out, and PTT. These three connections allow full digital mode operation.
考试技巧
Digital interface = Audio in, audio out, PTT. Remember: A computer-radio interface for digital modes needs receive audio, transmit audio, and transmitter keying (PTT). These are the three essential signals.
记忆口诀
**D**igital **I**nterface = **A**udio **I**n, **A**udio **O**ut, **P**TT (think 'DI = AIAOP')
实际应用示例
You're setting up a digital mode interface between your computer and transceiver. You connect: (1) transceiver audio output to computer audio input (receive audio), (2) computer audio output to transceiver microphone input (transmit audio), and (3) computer PTT control to transceiver PTT input (keying). With these three connections, your computer can decode received digital signals and encode/transmit digital signals.
错误选项分析
Option A: Incorrect. Receive/transmit mode, status, and location are CAT control functions, not the essential audio/keying signals needed for digital operation. Option B: Incorrect. Antenna and RF power aren't part of the computer interface. These are separate from the audio/keying interface. Option D: Incorrect. NMEA GPS and DC power aren't part of the digital mode interface. GPS might be used separately, but it's not essential for the computer-radio interface.
知识点
Computer-radio interface, Digital modes, Audio signals, PTT control
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.