Draytek Vigor 2200VG User Manual page 120

digital form it receives. This function is very useful when network traffic
congestion occurs to maintain the accuracy of DTMF tones.
DTMF Payload Type
The default value is 101, but can be anything from 96 to 127.
SIP Info
Enable this option to let the SIP proxy send DTMF tones to the dialed
peer.
RTP
Specifies the start and end port for RTP stream. The default values are
10050 and 15000.
VoIP Setup
9-11