What is DTMF?
DTMF tones are sent when browsing voice menus. Ask your VoIP provider which DTMF type to use with your account.
Configuring wha DTMF type to use
If you experience issues while navigating Voice menus, you might need to use a different DTMF type.
Ask your VoIP provider which DTMF you need to use with your account.
Run Zoiper, go to Settings -> accounts and select your account.
Open it for editing, then scroll right until you reach the "Features" screen.
There you can change the DTMF type according to your provider's recommendation.