FCC Question Pool Review

Technician Class (Element 2) • 2022-2026

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Question T4A07

From subelement T4 - T4A

T4A07
Answer: C

Which of the following connections is made between a computer and a transceiver to use computer software when operating digital modes?

AComputer “line out” to transceiver push-to-talk
BComputer “line in” to transceiver push-to-talk
CComputer “line in” to transceiver speaker connector
DComputer “line out” to transceiver speaker connector

Why is this correct?

The computer's "line in" connects to the transceiver's speaker connector to receive audio from the radio. This allows the computer to "hear" incoming digital signals for decoding. The speaker connector provides the audio output that would normally go to a speaker, but instead feeds into the computer for processing by digital mode software like WSJT-X.

Memory tip

Remember the data flow direction: "line in" means audio going INTO the computer, so it connects to audio coming OUT of the radio (speaker connector). Think "computer listening to radio" - the computer's ear (line in) connects to the radio's mouth (speaker out).

Learn more

Computer-radio interfaces require three essential connections for digital mode operation: receive audio (radio speaker to computer line in), transmit audio (computer line out to radio microphone input), and transmitter keying (computer controls when radio transmits). The speaker connector provides audio at the proper level for computer processing, while the microphone input accepts computer-generated digital signals for transmission.

Think about it

Why do you think the speaker connector is used instead of connecting directly to the radio's internal audio circuits?