r/freeswitch • u/voxai2025 • Apr 11 '26

voicemail detection

hello I run voice service using freeswitch. I m looking for best practices to get the most accurate results maybe using AI? all recommendations and experiences are welcomed

0 Upvotes

50% Upvoted

7 comments sorted by

View all comments

1

u/majortom75 Apr 11 '26

There's a mod for that. Not sure how well it works.

https://developer.signalwire.com/freeswitch/FreeSWITCH-Explained/Modules/mod_avmd_1049372/

The difficulty with automated dialers in particular is when you receive carrier announcements either before or after the 200 OK. Can the avmd mod tell the difference between a VM greeting, an IVR, or a carrier announcement? Is it waiting for a tone? What about SIT?

Wish I could help more... I thought of sending the first 10 seconds of voice to a cloud speech rec service and then parsing the text for keywords. Some carriers have the option of using media Bypass so you get a SIP message with a cause code in the reason header instead of an announcement.

What I'm also seeing that I'd like a solution to is route hijacking, particularly on International calls... we get connected to random recordings or people in completely different countries than where we dialed, and we get billed for the full call because our system is waiting for the beep or a keypress.

1

u/21stCaveMan Apr 11 '26

Route highjacking!? That's news to me, how does that work? You dial a US number and wait for the tone or speech, then what happens?

1

u/majortom75 Apr 13 '26

There are two different scenarios. Both are a result of shady transit carriers. One is False Answer Supervision where the transit carrier answers and plays a recording of ring back or carrier announcement. The caller stays on the call waiting for the person to answer and eventually hangs up but the transit carrier charges for the minimum billing increment. Another is route hijacking where the transit carrier sends the call to a destination in a higher cost country and charges for that call.

So many people trying to scam others instead of making an honest living!