Prowid course material: https://kurslar.prowid.com/en/index.php?id=lesson&m=3122
The PSTN Telephone Network: Subscriber Line, DTMF, Exchange, CAS · DTMF: tone dialing
The DTMF receiver: filters, the Goertzel algorithm in plain words, false detections (talk-off)
🔒 This is the beginning of the lesson. The full lesson is available with a subscription.