Unable to send the DTMF tones

If you are unable to send the DTMF Signals to an IVR or Voice Mail System or in case when you press the keys on the Polycom IP phone to pass the information to an application (e.g. Door entry system) and it does not work then you must check the configuration of the Polycom phone for the following string:

tone.dtmf.rfc2833Control = “0”

Please follow the steps below:

  • Access the web interface of the phone and go to Utilities –>  Import / Export Configuration.
  • Under the Export Configuration section, select “All configurations (except device settings)” and click on Export button.
  • Open the file you just downloaded and check if there is above string, if you do not find the above string in the file then add the string and save the file.
  • After saving the file, go back to the web interface of the phone and Utilities – > Import / Export Configuration.
  • Under the import section, browse the saved file by clicking on the choose file button and then press the import button to import the updated file.

Once the phone has finished off the rebooting process, you will be able to send the DTMF tones according to the RFC2833 standard.


Voispeed Help: https://www.voispeed.co.uk/ui-voispeed

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