When VoIP service is down /the network Link is down, can Line 1 automatically switch to PSTN service?
To enable this feature, set < Auto PSTN Fallback > to "yes" (under Line 1). When VoIP service is not available, the Line 1 phone will automatically call the FXO account and then hop on to PSTN network. If < VoIP Answer Delay > is not 0, the user will hear ringback right after he picks up Line 1, followed by outside dial tone. If < VoIP Answer Delay > is 0, he will hear outside dial tone immediately. The dial plan < Line 1 Fallback DP > will apply in this case.