Repeating intro prompts on call queues

[MrKoen]

Hi all,

every now and then my test setup is suffering under a weird problem with a call queue. Up till now I am unable to resolve it. I'm hoping one of you has encountered this before and knows an answer.

The problem arises when there's an incoming call to a call queue. The call queue is configured with a custom MP3 intro prompt followed by a custom MP3 for the on hold music. Every now and then, the intro prompt gets played multiple times. It starts off by playing the intro correctly and the phones in the call queue start ringing. Then the on hold music starts. After one or a few seconds the intro file gets played again while the on hold music is still playing on the background. This can occur multiple times and the repeating sometimes occurs before the intro prompt has finished playing. When this happens, usually the configured 60 seconds wait time is not met either and the destination if no answer action is performed after approximately 20 seconds already. It only occurs when having an incoming external call. It doesn't matter if this is through a Linksys SPA3102 device from a PSTN line or directly from a VOIP provider into the 3CX. It never happens when using a phone directly connected to the 3CX PBX and calling the call queue. It doesn't seem to make a difference if there are just two agents active in the call queue or more. I've had this weird experience in 3CX PBX v7 and now also in 3CX PBX v8 beta. The logs show no weird things. Also not under verbose mode. It does show the call being forwarded to the "destination if no answer", but it shows no reason for doing this before the configured 60 seconds timeout. I can't figure out when it does work correctly and when it doesn't.

I have attached the verbose output of the 3CX PBX during an incoming call where this problem occurs.

I have 3CX installed on a virtualized instance of Windows 2003 Enterprise Edition with Service Pack 2 running on the HyperV platform with Windows 2008 R1 Enterprise with Service Pack 2. I already lowered the amount of virtual CPU cores to one to make sure that's not causing any problems. It doesn't resolve the problem. Memory and CPU availability do not seem to be causing the problem.

Does anybody have a clue how I can resolve this issue?

Thanks in advance for any advice you may be able to give!

 

[LeonidasG_3CX]

Hi there,

What gateway are you currently using?
This behavior can be seen by pressing 8 while you are in the queue.

 

[tpinnovations]

It could be your mp3 time phase is being distorted, perhaps by the VMware. Can you perhaps try the MP3 on a 3CX install not in VMWare and see if it performs as designed?

 

[MrKoen]

Thanks for your replies guys. I also thought about the custom MP3 to be the problem. I can't find specs from 3CX as to what the MP3 encoding most comply. The strange thing however is that it does work fine when calling within the 3CX PBX network to the call queue. Another strange thing is that the 3CX PBX seems to lower the volume of the on hold music when it plays the intro MP3 again, just like it does when announcing the position in the call queue. I have the position announcement turned off in my setup by the way. I will try to set up a physical test box and see if that makes the problem go away.

I was also thinking about the ISA 2006 gateway to be the problem. I read many people to have problems using 3CX PBX behind a ISA firewall. I haven't experienced any problems so far though. This could explain why the call directly from the VOIP provider (Betamax - VoipBuster) could cause problems, though the incoming call from the PSTN line is routed over the internal network and doesn't use NAT on its way. Also the call after going through the call queue is perfectly fine of quality, without any hiccups, stuttering or echoes, so that kind of rules out the ISA as being the cause I would say.

LeonidasG, could you clarify your remark about pressing 8 while being in the call queue? Not sure what you mean by that. Do you possibly mean pressing the asterisk ( * ) while being in the call queue? This indeed makes the destination if no answer action perform immediately, though this key is not pressed.

Could it have something to do with that I have 6 Voip clients registered in the call queue and set as being available for calls from the queue, though only three of them are logged on? Is there a way to pull info from the 3CX PBX as to why it plays the intro MP3 or why it performs the destination if no answer action? Could it be that one of these 6 Voip clients in the call queue has some setting which "confuses" the 3CX PBX?

Thanks for thinking along!

 

[LeonidasG_3CX]

This shouldnt be a Voip Client Issue...


As i said before the only thing that comes in my mind is that...

Make a call to a Queue
While you are in the queue waiting for your call to be answered Press 8.
This should Make the Intro Prompt Repeat it's self.


Another theory i had was that maybe the Provider was registering on small intervals causing the Intro Prompt to be played, but i tried this unsuccessfully.

8Bits 16Khz Mono is the Supported 3CX Encoding... But you can still use even higher standards if you like they will still work with better quality but in some cases the audio may not be good and may cause freezing or other issues.

 

[MrKoen]

I haven't had the time yet to record the prompts again using different audio quality settings. It also didn't occur anymore since my posting. The behavure was indeed the same as when I would press 8 during the voice prompt, it played again. I also notice that sometimes during a phone call I hear a beep like the other party presses a number on his/her phone while this person doesn't do this. I'm guessing for some weird reason the Linksys SPA3102 is "inserting" these tones into the conversation. No clue as to why and when this happens though. If somebody runs into the same problem and finds an answer, please do post your thoughts and findings in this topic.

 

[LeonidasG_3CX]

I can do something similar with my Aastra by pressing 123 fast.

When i press 123 within 1 second, the callee connected to my phone hears 12343. Because of the rarity of dialing sending DTMF's that fast i never looked into it.
But in your case you just hear DTMF's out of nowhere, i'd say it is "Human Error" maybe the person calling you is indeed press Dtmf's.

Other than my Aastra Issue, i cant think of anything that represents the weird sounds coming out of your phone... A Ghost maybe?

 

[MrKoen]

Hehe.. then the next question would be.. how to get the ghost out of the phone?