Programmaticaly eavesdrop on all ongoing calls in real-time

Hello Asterisk community.

We’re working on a product that guides call center agents in real-time during the conversation.

We run speech-to-text, and different ML models on top of voice traffic (we need wav, but it can be RTP with any voice codec), and we have to identify particular conversation/agent/caller/call start/call end (basically signaling).

We want to be able to integrate with as many Asterisk appliances as possible in the least intrusive, and the most sane way.

How to achieve this?

So far, we came to several approaches, looking at the documentation, each with it’s own drawbacks:

  • C Module seems to give us what we need, but a bug in our code may crash client’s installation, and also updates become much harder.

  • ARI seems like the ideal solution (is it possible to stream voice/media data over ARI?) but the API is fairly new, and some of our clients may not have it.

  • AMI looks like the way to go, but I couldn’t find how to get the voice/media data using AMI (as far as I understand, additional integration with AGI is required in our case to get voice)

  • I’m not sure yet if it’s possible to integrate with AGI only, but the drawback in this case is that bug/delay in our application again may draw some of the calls unstable, and we’re trying to avoid that

  • We’ve made a proof of concept with tcpdump, capturing raw SIP/RTP traffic, it works for us but unfortunately we also may capture client’s sensitive data, we don’t want that, and some of our clients won’t allow us to do so.

Please correct me where I’m wrong, as my knowledge of Asterisk is pure theoretical, and guide me in the right direction.

Thanks in advance

I think ARI is most comfortable way to attach to existing , running
asterisk system by less intrusive.
to capture RTP, you attach chan_spy to the running channel - and collect
stream on your own remote recording server, run speech2text and do not
overload a running asterisk.
To control , you can send any DTMF, play sound to the channel, extracting
channel info for tracking purpose.

All you need - access to ARI interface .

AGI require modifiction of dialplan and upload scripts to remote server ( or
use remote AGI )

Thank for the answer. I will look into chan_spy

Thanks again for your answer,

I’m looking how to work with chan_spy, and I see it’s possible to attach it to the channel where I am an originator.

What we need is to listen to all calls, as a third-party. So that call center runs as usual, and we’re receiving voice traffic from all the agents.

Can you point me to the relevant part of the documentation? At the moment I’m a bit lost.

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