[asterisk-users] "Follow me" with Asterisk that detects cellphone voicemail and similar announcements

[Robin Kipp]

Hi all,

sorry if the subject is a bit confusing, but I just couldn’t think of a good way of better describing the situation…

Basically, I travel a lot and have several SIM cards for my phone from local carriers. What I’d like to do now is to setup Asterisk, so that people who want to reach me just have to dial one number which forwards the call to all my cellphone numbers in turn. I’m still pretty new to Asterisk, so I’m unsure which method would be most suitable for this scenario.

Theoretically, I could use the dial function to call one number, then wait a few seconds and then dial another number. In practice, this won’t work because as soon as a call is answered by the mobile carrier’s voicemail the caller would be connected to that, no other numbers would be called.
So here’s my question: how can I possibly avoid this situation? Is there a way for Asterisk to detect such situations and distinguish them from me actually trying to answer the call when the correct number is called?
Not sure if this is technically possible, but figured I’d ask just in case there is any sort of solution. I’m aware that it would be best to simply use SIP and a SIP client on my phone in order to take the call, but due to most carriers blocking SIP traffic on their mobile data networks this wouldn’t work as soon as I’m not connected to any WiFi.
So, in case there’s any solution to this problem I’d greatly appreciate if you could share that with me!
Many thanks and best wishes,
Robin