Hi,
I have found in the web that following information about busy tone of my country:
Tone: Busy Freq: 480 + 620 Amp: -13 Cadence: 0.5 seconds on, 0.5 seconds off,REPEATED
What is the meaning of "Freq: 480 + 620"? Is it a dual tone frequency?
If yes, could I calculate its existence by just a timer?
I can get rectangular waves in the telephone line using call progress filter.