Which of the following is a tone of two combined frequencies that lasts for .5 seconds and repeats after .5 seconds of silence?
A) Busy circuit
B) Busy signal
C) Carrier wave
D) Cell

Question

Quizplus · Accepted Answer

A busy signal, which is a tone of two combined frequencies that lasts for .5 seconds and repeats after .5 seconds of silence, indicates that the line is currently in use.

Which of the Following Is a Tone of Two Combined