Issue with 3CX External Extensions (One Way Audio)

[jzollo]

Hello All,

I'm having a serious issue with one of our clients. Previously I was able to resolve this by selecting "PBX Delivers Audio", but now it doesn't seem to be working properly. Every time we make a call, the individual on the extension cannot hear whoever he or she is talking to, but they are able to be heard.

For example, I call in and External Extension 500 picks up, I can hear them but they cannot hear me.
Another example, External Extension 500 calls me on my phone, I can hear them, but they cannot hear me.

I cannot run the firewall checker without bringing down the phone system, this would be something I have to do at a later time, after they close for the day.

I would greatly appreciate any insight!

 

[davidbenwell]

Hi this is a firewall / port forwarding issue

If you have more then the one remote extension at the same remote location then you will need to use the 3CX Proxy Server.

 

[jzollo]

Right now we're only dealing with two remote extensions in separate locations. Both users are experiencing the same issue.

The strange thing is, when I make a call from my computer (i'm also in a remote location) to my cell phone, two way audio works fine.

How would we go about enabling the 3CX Proxy Server?

 

[nbailey]

Hello!

Please find the attached link to help you setup the SIP Proxy Manager. http://www.3cx.com/blog/releases/sip-proxy-manager/ The problem with Remote Extensions is that depending on your Router/Firewall and Port Forwarding settings it can work for one site and not for another. The SIP Proxy Manager will help you overcome NAT issues.

Good Luck!

Nate

 

[jzollo]

Thanks to both of you for your suggestions, we'll be getting that setup ASAP!

 

[eagle2]

Using the 3CX proxy server at remote location will definitely solve the problem, as well as using 3CX tunnel with 3CX softphones, or other tunnel implementations.

The problem is related to the router / NAT at the remote site. What phones are you using ? If using Cisco / Linksys SPA phones or other brands supporting symmetric RTP, you can try switching it on. Check also what is the remote extension registration address, the issue could be improper STUN resolution. Can you debug the remote site with wireshark ?

Regards.

 

[SY]

System extension *777 was created to simplify troubleshooting of audio delivery.