Send 486 code when trunk limit reached

[bigdessert]

We are running 3CX 16 Update 4 on Debian 9.

We have trunks with a call limit set on them. When the max calls are in use if someone tries to call in the carrier receives a "600 Busy Everywhere" code and in turn forwards it on as a 404. According to a thread here a 3CX support rep says it is supposed to send a "486 Busy Here" but that is now what we are experiencing. Is this something that is configurable or is there a way around this as I need it to send 486 instead of 600.

Here the old thread where the tech says it should send a 486:
https://www.3cx.com/community/threads/busy-on-incoming-sip-calls.58455/

Here is a page stating it will send the 600:
https://www.3cx.com/docs/sip-trunk-options/

 

[leejor]

When the max calls are in use if someone tries to call in the carrier receives a "600 Busy Everywhere" code and in turn forwards it on as a 404.

So...3CX is sending the 600 to your provider, who in turn forwards it on as a 404? If that is the case, then it sounds like something you should be discussing with your provider. Perhaps they have the ability to change the 'conversion".

The first link you posted is about a year and a half old, which may be out of date. I would tend to go with what the Trunk Options post says. I'm sure that someone at 3CX will comment on which is correct.