Still no busy tone when callee is busy

[narkumas]

Hi,

this happens not always. It happens only with certain destinations.

We are calling a number and when it is busy, we get no busy tone. only silence.The Activity Log shos it is busy. So why no busy tone?

09/29/2017 8:55:56 AM - Call to T:Line:10000>>04027818053@[Dev:sip:[email protected]:5060] from L:305.1[Extn:312] failed, cause: Cause: 486 Busy Here/INVITE from 213.148.136.222:5060

 

[mic.max]

have you selected correct country tone for your provider ?

 

[narkumas]

I have no idea. Where do I have to set it?

 

[narkumas]

Are there countries where You have no busy tone?

 

[narkumas]

Noone in the wide world who has an idea?

 

[leejor]

Have you tried toggling the BUSYPROMPT in the custom parameters table?

https://www.3cx.com/blog/docs/3cx-phone-system-parameters-table/

Both options are simply a file. Does one work, but not the other?

 

[narkumas]

No, I did not. Because both files are the same in my environment.

 

[YiannisH_3CX]

So in certain destinations busy tone is heard and in some it is not? Navigate to settings / PBX and check if the option Play busy prompt when extension is busy is selected or not.
If it is then un-select it and try again. If the issue persists then you will need to run a wireshark capture to see what is coming different from the provider in the cases that the busy prompt is not heard.

 

[narkumas]

Yeah, it is really strange. it happens in certain combinations of caller and callee.

meanwhile my reseller has created a ticket and the support bundle has been submitted.

 

[YiannisH_3CX]

Do you have the ticket number so i can keep an eye on the progress?

 

[leejor]

Is there a pattern? Calls to numbers "belonging" to a certain provider always doing this? Are there differences in the SIP message received, when the line is engaged, on a call that a busy tone is heard, and one that it isn't, (taken from the 3CX Activity Log)?

 

[lneblett]

Get a capture of the call. From what little you posted, it appears that an external call was made to a given number from extension 312. During the call attempt, the 486 busy message was sent as the response. As this was a SIP call, we really do not know who originated the response and to where the response was ultimately sent. I assume that upon receiving the response, 3CX relayed the message to the phone whereupon receiving same, the phone would either display the message about the response or actually provide the Busy tone. Some phones may have a setting that indicates the desired action - display or audio. The 486 response may have been generated somewhere along the path to the destination without ever having made it all the way. It may depend on the actual condition encountered, the resultant message generated back and then how your provider interpreted it and relayed to 3CX.

When you do hear the busy tone on other calls, I suspect that 183 session progress has occurred. This is when instead of the 486 message, the call has actually progressed to the destination and you are hearing the busy tone as generated by the far end provider as the audio stream has already started to flow (early media). This is more akin to an analog call and is what most people expect.