I cannot send DTMF tones to the door opener from the Polycom IP6060 phone

When we have to send the tones from the Polycom IP telephone to an analog adapter in door opener / door entry panels applications and it does not work (connecting an analog telephone instead of the door entry panel we do not hear the tones pass) we must check that in the Polycom telephone configurations there is the following string:

tone.dtmf.rfc2833Control=”0″

To do this, is it necessary to access the web interface of the phone, go to the Utility section? Import / Export configuration? Export configuration, select “All configurations (except device settings)” and click on export.
Open the file you just downloaded and check if the above string is present: if it is not present, add it. After saving and closing the file, return to the phone’s web interface in Utility? Import / Export configuration? Import configuration, browse the HD and choose the file you just saved and finally press the “Import” button.
After the phone is restarted it is possible to send DTMF tones according to the RFC2833 standard.

As for the FXS V-6016 adapter, to which the telephone interface is connected, it must be configured to send tones with RFC2833 and the payload must be set to 127.