I’ve got a couple of locations that are having the same problem. This has been going on for … ever (3yrs).
They all have this in common:
Rhino Ceros box
PRI (Rhino PRI TDM)
Users have a problem hearing DTMF tones during a conversation.
I can change:
In the web GUI on the Aastra handset - "Global SIP" section, make the following changes:
Under RTP Settings:
Force RFC2833 Out-of-Band DTMF - UN-checked
DTMF Method - changed to SIP Info
That will correct the DTMF issue, but then touchtones will not be recognized if you dial into an interactive menu e.g. enter your CC number using the touchpad, some of the digits are heard twice or not at all.