How to Set Up DTMF

  • Published on Nov 29, 2024
  • 1 minute(s) read
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Basic Concept

What is DTMF?

Dual-Tone Multi-Frequency (DTMF) is a signaling method in telecommunication systems for numerical inputs. It allows users to unlock doors by pressing a DTMF "Unlock" button or entering a code on the keypad during a call.

How is DTMF Transmitted in SIP?

In the Session Initiation Protocol (SIP), there are three primary methods for transmitting DTMF tones:

Inband DTMF

Out-of-band DTMF (RFC 2833)

Out-of-band DTMF (SIP INFO)

  • Sent within the audio stream.
  • Simple but less reliable due to potential sound quality issues.
  • Sent via RTP packets as per RFC 2833.
  • Reliable and widely supported.
  • Sent as SIP INFO messages.
  • Reliable but less commonly supported.

Set Up DTMF on the Akuvox Cloud

1. Click for the site you want to configure.

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2. Click the 'Intercom Devices' button, then click  for the doorphone you want to configure.

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3. In the Edit Device window, Relay 1 is enabled by default for each doorphone. You can assign a DTMF code from 0 to 9, or use '#' or '*' for each relay. Additional relays can be added as needed. In my case, the user will use the '9' button to unlock the door during a call.

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