When SIP software offline => long silence before Voicemail

[mstolle]

Hello,

I have a weird problem. I have a DID set up through IPKall, which works fairly well. Usually I have a Nokia Internet tablet connected to Voxalot and it rings fine. I can reject the call or wait some time and the call goes to voice mail, no problem.

However, if I leave WiFi or unregister from voxalot, the call does not get immediately forwarded to voice mail. Instead, the caller gets silence for some time (about the time it takes for voice mail to pick up), and only then it gets to voice mail. However, the lack of ringing seems to be causing problems, as depending on who calls in, this causes one of the following symptoms:

- caller hangs up before voicemail because they think something is wrong
- caller gets "this number is no longer in service" ?!
- caller gets perpetual silence (never hears voice mail), but at some point a garbled voice mail is recorded

None of this happens when I get the call and ignore it and/or reject it. In those cases, voice mail works as expected. However, in the problematic case, as there is no ringing signal sent to the caller, Voxalot (?) must be detecting that my SIP client (Nokia Tablet) is not receiving the call. However, for some odd reason, it is not forwarded to voice mail quickly - instead a silence is sent that seems to be confusing callers (people and networks).

Thanks,
Martin

PS: I verified the "silence before voicemail" is also happening when calling from another SIP client.