Problem
I have set up a SIP PBX via a Beronet gateway to an ISDN system connection, everything works well.
Only when I call out I get no dial tone, it is just quiet until the subscriber takes the call!
Solution
Create a call progress entry.
webGUI/Preferences/Call Progress
add table -> name: Ringing -> Direction: SIP-ISDN
SAVE
add entry -> Interface type: NT/TE( depends on the ISDN port is in NT or TE mode) -> ISDN event: proceeding -> ISDN channel details: any_state -> SIP response: none
SAVE
webGUI/SIP/SIP+/Provider/more/Call Progress Table S2I: Ringing
SAVE and ACTIVATE.