Prowid course material: https://kurslar.prowid.com/en/index.php?id=lesson&m=3123
The PSTN Telephone Network: Subscriber Line, DTMF, Exchange, CAS · DTMF: tone dialing
DTMF inside the voice channel: IVR, post-dialling, passing through the network and DTMF-CLIP
🔒 This is the beginning of the lesson. The full lesson is available with a subscription.
