Strange ring sound when calling

I have for some companies 4 freepbx around the world with the same sip provider, g729 codec,freepbx version, vdsl bandwith and proxmox virtualization platform. the only differences are the ip phones that in 3 of 4 pbx are grandstreem but in the last pbx are fanvil, and the router beetween freepbx and the vdsl is pfsense for three of four pbxs but is a mikrotik for the last one. The issue that I can resolve is related to the ring sound that the caller is listening in this last pbx with fanvil phones… is like flickering, and this is little annoying cause looks like a poor quality system.
this is the perfect ring of the 3 pbx


and this is the ring of the last one with fanvil

I really don’t think that this is related to the ipphones… maybe is something with the codecs, but switching from g729 to any other codec does’t changes anything. voice quality is perfect and is the same in all the 4 pbxs. any suggestion?

The ‘good’ ring is EU standard. Your ‘bad’ ring is North America style.

The provider can indicate ringing in 3 ways. A SIP trace will show which is being used:

  1. By sending 180 Ringing status, without associated audio. In this case, the phone decides what ringback tone to play (unless you have Inband Progress set for the trunk, which you shouldn’t). If that’s your situation, set Tone Standard in the phone – see http://www.fanvil.com/images/user/UserManual/20171211X2C.pdf p. 50.

  2. By sending 183 Progress with associated audio. In this case, the phone should play whatever is being sent. Conceivably, the provider is sending something different to the system with the Fanvil phones, perhaps because of the outbound caller ID or the country indicated by the IP address.

  3. By sending 180 Ringing with associated audio. In theory, this should work the same as case (2), but pjsip trunks sometimes have trouble with it. If that’s what you are seeing, try switching the trunk to chan_sip.

If you still have trouble, post a SIP trace and audio captured from the RTP stream sent by the provider (use alaw codec so Wireshark can decode it).

you really were really clear… I didn’t know about the difference from America and Europe ring tone…anyway… I found that using an extension as inbound route destination the tone becomes the european one, instead using a group as destination the tone becomes like the US one. But this is really strange cause in the fanvil that I set as destination for this testing the tone standard was US… maybe is there a difference if the destination is a group? or I have to setup every single phone in my lan with the european tone?

ok I found the solution, it was under advanced settings


thank you for poiting to the right direction again.

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