No audio on internal calls external calls work fine

[bevans9908]

Hi,

I have a situation where internal calls can be completed but there is no audio on either end. However, on external calls, both inbound and outbound, everything works fine.

I get this in the activity log for each internal call: 08/26/2021 3:00:33 PM - [CM503003]: Call(C:128): Call to <sip:[email protected]:0> has failed; Cause: 487 Request Terminated/INVITE from 127.0.0.1:5483

I see the INVITE IP address is showing a localhost address and I'm guessing this is the problem. However, I have no idea how to resolve that if it is the problem. The instance is hosted with 3CX.

Any help would be appreciated.

 

[JohnS_3CX]

Hi @bevans9908

Give us some more information so we can understand the deployment:

- Are you using STUN or SBC?
- What model phones are being used?
- What firmware version are they running?
- Are the phones on the same subnet as each other?

 

[bevans9908]

Hi @bevans9908

Give us some more information so we can understand the deployment:

- Are you using STUN or SBC?
- What model phones are being used?
- What firmware version are they running?
- Are the phones on the same subnet as each other?

Hi @JohnS_3CX

I'm in the process of looking over the network config so I can't yet answer the last question. Because this was literally a physical phone swap from the old system to the new, I assume they are all on the same subnet. However, I didn't build the network so I have to confirm. I'll get back to you later on that question. Here are my responses to your other questions:

- I am using STUN
- Fanvil X4U and X3SG phones
- X4U running version 2.4.11 and X3SG running 2.4.10

I'll be in touch later once I'm done looking over the network config.

 

[JohnS_3CX]

Hi @bevans9908

Ok, when STUN is involved you need to make sure the phones requirements are met in order to get reliable service.

Alternatively, if you have more than just a couple of phones at that site, consider using an SBC which pretty much does all the work for you without needing to mess with the firewall or use static IPs on phones. It can even run off of low cost a raspberry Pi and believe me it does earn its keep

 

[Saqqara]

As above - install an SBC server - will save you alot of hassle

https://www.3cx.com/docs/3cx-tunnel-session-border-controller/

 

[bevans9908]

Hi @bevans9908

Ok, when STUN is involved you need to make sure the phones requirements are met in order to get reliable service.

Alternatively, if you have more than just a couple of phones at that site, consider using an SBC which pretty much does all the work for you without needing to mess with the firewall or use static IPs on phones. It can even run off of low cost a raspberry Pi and believe me it does earn its keep

Many thanks for the info! I will take a look and see if I can figure something out.

The business is closed today so I don't have access to test but I'll be in touch once I know more...

Thanks, again!

 

[bevans9908]

Thanks, @Saqqara. I'll check it out.

 

[bevans9908]

Thanks again, everyone for your suggestions. The fix turned out to be very simple and was part of the info @JohnS_3CX shared. I just had to enable the "PBX Delivers Audio" setting in the Options > Troubleshooting area of the user settings.

Note to self: Buy a later model phone in the future.