@tps1212 . Do you have equipment that responds to DTMF tones?
Is it all callers to your number having this problem or just some?
In Advanced, Bandwidth Control is a setting: Telephony Bandwidth Guarantee:
Enable Telephony Bandwidth Guarantee to ensure sufficient bandwidth for Telephony service.
You can try enabling this.
Distortion of tones sounds a bit like this from the VR1600 manual. RFC2833 is the best method to use.
This version of firmware doesn't have any access to this setting. It may default to this value.
DTMF Relay Setting: DTMF is Dual Tone Multi Frequency. Options available are SIP-Info,
RFC2833, and In-band. If you are unsure which one to choose, please always keep the
default value.
• SIP INFO: If it is selected, the modem router will capture the DTMF tone and transfer it
into SIP form. Then it will be sent to the remote end with SIP message.
• RFC2833: If it is selected, the modem router will capture the keypad number you
pressed and transfer it into digital form then send to the other side; the receiver will
generate the tone according to the digital form it receives. This function is very useful
when the network traffic congestion occurs and it still can remain the accuracy of
DTMF tone.
• In-band: If it is selected, the modem router will send the DTMF tone as audio directly
when you press the keypad on the phone.
