"Busy here" when lots of calls

Hi everybdy !!

I post a message here because i don’t know what to do to find a solution to my problem.
I manage a quite big asterisk/FreePBX pbx in my office.

FreePBX 12.0.45 (Located in France)
25 Sip users
First trunk : 15 lines
Second trunk : 5 lines (Backup trunk if congestion problem on the first one)
Third trunk : 1 lines (International calls)
Fourth trunk : 2 lines located in USA

90% of the traffic uses the first trunk.

There isn"t any problem when i have only between 2 and 3 simultaneous calls. But, when our callers starts to work, i have up to 14 simultaneous calls and usually BUSY HERE messages appears on the phone.

Just for today : Around 100 unexplained BUSY calls.

What is surprising is that it can be BUSY on the first and the second trunk. (But usually, if call is not possible using the first trunk it uses the second one and it runs.

I already checked that there is no limit in the TRUNK configuration, i checked that i effectively have 15 channels with my SIP provider.

Don’t know what to do …

The log file doesn’t give anything interesting. I try to see with our sip provider what is answering their server.

Any idea ?

Bye !!

The log file will generally log a cause code as to why a particular call didn’t complete, look at the logs again , this time more carefully. Limit specifically the number of outbound channels in the trunk and force try next trunk if the carrier returns an inappropriate reason (that’s all in the pop-up help on the trunk page)

A quick way to also see is in the CDR’s you will find the system link displaying the details of the call.
If you called a number and the first provider failed, it should then go to the next provider and so on, until finally etiher completing the call, or timeing out from attempting the call to each provider.

Looking at the logs always has more information as dicko rmentioned.

Thank for your answers. When i take a look in the log files i see this error :

"Dial failed for some reason with DIALSTATUS = BUSY and HANGUPCAUSE = 19") 

Dial failed for some reason with DIALSTATUS = CHANUNAVAIL and HANGUPCAUSE = 1"

Nothing else in log files.

That’s all you need

Cause No. 19 - no answer from user (user alerted). (check with your provider as to why they are ignoring you)
Cause No. l - Unallocated (unassigned) number. (this is an ‘inappropriate’ response)

either way try my previous advice as to how to setup your trunks and check your outbound routing.

I should have an answer from tech support tomorow.


The outbound route is set up to match all calls (.X rule) and send it trough first trunk and then second one.
The trunk configuration is set up to “Try next trunk”.

A question in my mind : If the outbound route is already set up to try the second trunk if the first fails, is it useful to keep “try next trunk” in the trunk configuration ?

Thanks to spend time on my problem :wink:

Give you a feed back tomorow.

As both I and the “pop-up help” have already said , that will be necessary if your provider replies inappropriately, and yours does, I’ll let you figure it out from here :slight_smile:

Another question .
In my freepbx screen i have

1- COMPLETEL (First trunk)
2 - GEILUS (American trunk)
3 - OPENIP (Emergency trunk)

So i tough that if COMPLETEL fails, it tries GEILUS ad finally OPENIP

But, if i take a look in logs i see that COMPLETEL is N°2 and OPENIP n°3.

How can i find the trunk list as written in log files ?

Just follow the wiki


and notice the address of your “freepbx screen” a trunk page would show as

. . . . config.php?display=trunks&extdisplay=OUT_8

OUT_8 is the clue when debugging