Using Future Nine or the OBitalk config portal, is it possible to set up my service so that when my internet connection is working normally, incoming calls go to voicemail after, say, 20 seconds, but when the OBi device is offline for whatever reason, incoming calls failover to another number (e.g., my cellphone)?
I tried adding my cell # as a priority 2 destination for my DID (in the F9 config page), with a longer timeout than my SIP (priority 1) destination, but a test call got redirected to my cell instead of landing in voice mail.
edit to add: Would like to do this without Google Voice if at all possible
edit #2: I am using an OBi100, and will have no PSTN and just one VOIP provider in my ideal final configuration