Audiocodes

Enable MWI: Configuration→VoIP→GW and IP to IP→DTMF and Supplementary →Supplementary Services Message Waiting Indication (MWI) Parameters Enable MWI “ENABLE”

Only the extension @ gateway IP address is required 
**Example**
3101@192.168.100.243 
Note: This extension or phone number must be the number in Configuration->VoIP->HuntGroup>Endpoint Phone Number for the channel