Clarifications on "PBX Delivers Audio" and calls recording

[davide.bonavita]

Hello there!
I didn't really grasp what the option "PBX delivers audio" actually does. I've read a bit in the previous posts, but now I'm even more confused!
I understand that the best practice is to keep it enabled in the SIP trunks configurations and disabled in the extension's options. I also understand that if you don't enable it for the extensions the system is not able to record the call, because once the call is connected the PBX goes out of the scene and there's a direct connection between the sip provider and the extension, but weirdly (and luckily) with this setup I'm still able to record the calls.

Ideally, I would love to have the ability to record all the calls AND have the audio streams flow directly from the extensions to the VoIP providers (as both the providers and the agents are physically in South America while the PBX is in an AWS European regions, don't ask why lol)

 

[Alphabetic]

There are a few posts on here which explain this option:

"PBX Delivers Audio routes all audio traffic through the PBX. This helps in situations that the endpoints cannot talk directly between them or there is a network restriction that this option helps overcome. This does add additional audio to the PBX as all traffic needs to go through the PBX. This can cause audio issue if the server does not have the specs to handle the traffic or if the server and the endpoints use different codecs and the audio has to be transcoded
back and forth which does have an impact on quality.
When Call recording is on then audio is routed through the PBX anyway as it needs to be recorded.
For providers it is recommended that the option is always on as there are rare cases that the call might not have audio when connected to a remote extension. "

Are you having audio issues? You could always backup/restore your 3CX to a new instance closer to your SIP provider, up your resources on PBX or try using an SBC.

Our PBX is in UK and we're using CallCentric which is in the US and we have no problems..

 

[davide.bonavita]

Hi there, thank you for your reply!
So you're saying that the configuration is overridden when you record a call as it indeed has to go through the PBX. So what happens when I click on the record button mid-call if "PBX delivers audio" is disabled? will the record be silent as a direct connection is already in place?

BTW yes, some agents have quality issues while calling some LatAm countries, but it's really hard to tell what's happening, they just say "It works fine with Skype"

 

[JohnS_3CX]

Hi,

No it will not be silent, there will be a re-invite for both parties and this time the SDP will point towards the IP of the PBX instead. (internal calls scenario - using local windows clients)

Note though that if this is an external call, you are already sending audio to the PBX to begin with. Same if you are working over the tunnel or webclient.

 

[davide.bonavita]

Hello John, so if we're using the 3CX app or the chrome extension the audio for the outbound calls will pass through the PBX regardless of the settings?

 

[JohnS_3CX]

Not quite regardless of settings, it can depend:

Mobile clients = yes
Web client = yes
Browser extensions = yes

Windows client
Yes if remote
Yes if local + recordings enabled
Yes if local + PBX Delivers Audio enabled
Yes regardless of settings if calling out via your internet trunk

No if local + PBX Delivers Audio disabled and no recordings are enabled and if calling another extension with same scenario as this one.


So as you see
- the way you connect to the PBX will make a difference (Browser / Tunnel / Local)
- the destination you call will make a difference
- and recordings will make a difference

Hope this made it a bit more clear, I realize the internals can get a bit complicated

 

[davide.bonavita]

I'm gonna save this post, thank you John!

PS: sooo, since we' have our 3CX hosted in London on AWS and both the VoIP providers and the agents (using the chrome extension and with the auto recordings enabled) are based in US, makes sense to move 3CX in the US region to reduce the latency?

 

[JohnS_3CX]

Yep, that would make sense to keep it as low as possible