Something I changed in the last day is now producing odd behavior that I’m having a hard time understanding.
I have Asterisk set up with an X100P card connected to a PSTN line, as well as with an internet connection and a VoIP ITSP provider. Since I’m still in testing mode, I also have other analog phones connected in series on the PSTN line.
I can call in from any external phone on the PSTN line and get normal asterisk behavior (auto-attendant, call-screening, etc.). I can call in from an external phone on the VoIP line and get normal behavior.
But if I call OUT on the PSTN line from one of the house extensions (so the outbound leg is purely analog phone->PSTN) IN to the VoIP line, in addition to getting the normal inbound behavior on the VoIP line (auto-attendant, etc.), Asterisk ALSO answers the Zap channel on about the second ring (resulting in two live channels going on at the same time, and about 10 seconds out of sync)!
After thinking about this and repeating the behavior for the last couple of hours or so (and proving that this seems to be the ONLY case in which this bizarre behavior occurs) I’m wondering if somehow Asterisk is fooling itself by detecting (and answering) the ringing on the outbound analog channel, even though it’s off-hook and can’t POSSIBLY be generating an inbound call? This doesn’t really make sense, but I don’t understand enough about Asterisk or the PSTN to know if that’s what’s going on, and this explanation sure SEEMS to fit the behavior. (FWIW, I do have call-waiting on the PSTN line, and have callwaiting enabled on the zap channel, though these settings have not changed in weeks.)
Admittedly this is not a normal call to make, and it’s not a showstopper if it doesn’t work right, but a) I’m curious why this is happening; b) it is a convenient testing mode that I’ve used in the past that no longer works; c) I’m worried about some misconfiguration that is going to show up as a more serious problem.
Hoping someone can explain what’s going on and if there’s a way to avoid it.