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Digital Receptionist Random Amounts of Responsive?

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TagleRock

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Hello Everyone,

We have 3CX deployed at a client with about 55 phones. It is hosted on Debian running as a VM on ESXI. Randomly when people call in the menus on the digital receptionist won't work, or they will work but you have to press the key for a long time or several times.

The first menu, which asks callers to choose between English or Spanish, almost always works, but the next menu, which has about 8 options, is the one that we have issues with. Anyone else had issues like this before? Anyone have any suggestions?

**EDIT** - Just found out we have a new issue, when pressing 1 or 2 for spanish to get transferred to the next IVR it doesn't do anything, you just get silence. This has never happened before. The server did go down unexpectedly over the weekend due to a power outage, but it turned back on with no issues, the recordings are all there, routes look good, and there is nothing in the error logs.
 
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Ok the latest issue was resolved by a reboot, but the same problem still remains, when trying to choose a option in the IVR it sometimes doesn't respond.
 
What type of trunks are you using...SIP, or a gateway? It may be a DTMF Method issue.
Do you have any issue if you try calling from an extension?
 
Sorry for the late response, been hectic at our office with covid. We are using their ISP for the SIP service, that service is being provided through an onsite SBC owned by the ISP.
 
You mean if I dial the IVR from an internal extension? If so inside, outside, or both (of the LAN)
 
If you call the IVR NOT using an outside trunk, so... from an extension.

If that works, then it narrows down the issue to your trunks. What Codec are they using? That may make a difference if DTMF is being sent as audio.
 
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Sorry for the late reply, got slammed with other stuff and couldn't get back to this. I provisioned the 3cx app on my cell phone with a test extension and called the ivr several times and tried several options and it worked each time. Althouguh i've done the same with and outside line and it worked, its pretty random when it happens. It did seem more consistent when I tried it internally though. When testing from the outside even if it works each time it would sometimes take it a bit longer to transfer me out of the menu to the option that i pressed.

The Codec being used is G.711 U-Law
 
I did some further testing and this is what i found.

When I send DTMF tones from our 3CX system to theirs (pressing keys on grandstream desk phone) it comes out as a DTMF tone with a fixed length. This tone is always the same length regardless of how long you hold down the key.

When I send DTMF tones from the 3CX app on my cell phone to the same deskphone provisioned to our 3CX in our office then i get only clicks, regardless of how long the key is pressed. These clicks change in frequency depending on the button that is pressed.

When sending DTMF tones from my cell phone (my cell phone number not 3CX) to another app on another cell phone joined to the problem system I get muffled sounding kind of clicks, thought it was just picking up my finger at first but i'm pretty sure it was the same clicks

When sending DTMF tones from the second app on the second cell phone to my cell phone number it would generate the fixed length tones.

So in summary....

Deskphone (our 3cx) -> 3CX app (my cell phone, provisioned to problem 3CX PBX) = Fixed length DTMF tones

3CX app (my cell phone, provisioned to problem 3CX PBX) -> Deskphone (our 3cx) = Clicks

My cell phone number -> 3cx app (another cell phone, provisioned to another extension on problem 3cx PBX) = muffled sounding clicks?

3cx app (another cell phone, provisioned to another extension on problem 3cx PBX) -> My cell phone number = fixed length tones
 
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TagleRock said:
We are using their ISP for the SIP service, that service is being provided through an onsite SBC owned by the ISP.
Click to expand...
No knowing how/if this is going to have any affect, you might contact your provider and ask them which DTMF Method they are using/sending. If you explain the problem, they may already be aware of a solution.
With audio DTMF...most digital devices will send a fixed length tone. It only tends to be older, analogue sets that will continue to send a tone for as long as the button is held down.
 
There are 3 types of DTMF the 3CX system supports. Inband, SIP Info and RFC2833.

Inband is audio tones send through the audio stream. Each button press generates a different tone and the system decodes the sounds to see what was pressed. This can be unreliable if there is jitter on the line or if some packets are lost as this will cause the tone to arrive distorted or incomplete.

SIP INFO is sending the DTMF tones through a SIP INFO message. Almost no one uses this method though and i don't think this method is related to your issue.

RFC2833 is the most reliable and the most used DTMF method in VoIP and all 3CX supported devices along with the 3CX clients use this method by default.

Contact your provider and see if the support RFC2833. If they do then run a packet capture and see what is actually being used and go from there. If they do not then look for a different provider.

You can also look at the activity log and find the Inbound Invite from the provider. Check if there is support for telephone-event.
 
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Hello everyone, been a while I know. I finally have had some time to revisit this issue. I did a wireshark capture when the problem occurred and analyzed the RTP streams. The call was from our 3CX phone system to theirs. The first menu recognized the press of the number 1 immediately. On the next menu I pressed 9 and it didn't work, I pressed it a total of 20 times before it did work, towards the end I pressed it more rapidly to see if that would make a difference. The tones in the play back sound like they should, they are fixed length DTMF tones that sound very clear, its like 3CX is just completely ignoring them. I'm going to see if its any different from my cell phone, but wireshark reported zero loss and when i look at the audio waveforms there don't appear to be any major differences that make 20 the magic button press.
 
Ran a test from my cell phone and did a capture on a working one to see what would happen. The DTMF was fixed length tones like before, but the waveform is different, almost like the amplitude is lower, either way it did work, despite a bunch of background noise captured because I had my phone on speaker. Going to see if I can get it to fail now when calling from my cell phone.
 
Well that was easy, only took a couple of tries before it went poo. It was the exact same thing that happened when calling from our office 3CX system. My cell phone would send fixed length DTMF tones. The first menu worked without issue, then the second menu when i would press 9, no matter how many times i did it or how rapidly i did it it would not recognize the input. This time i pressed it 30+ times and it did not recognize it, I also pressed "#" a few times to try and get it to repeat the menus options and it wouldn't recognize that either.

As I stated in the summary of what happens between our phone system and theirs, its like 3CX is just completely ignoring the input.

One thing i forgot to mention is that on this failure test i left my cell phone off of speaker phone to eliminate background noise as a variable. The DTMF tones were clear and had a similar waveform to the ones from our 3CX with little to not background noise.
 
Anyone have any ideas?
 
Hi TagleRock,

I've had a similar issue with a system I had set up recently. We have a SIP connect interface as well as an Internet access interface and a PFsense that was managing it all. The way it was resolved is by sending some traces to our SIP provider. They found 2 different IP Addresses on the call headers - I had not set the correct IP address in the SIP trunk settings.

1598446776195.png
This seemed to be causing the issue with DTMF tones not working and also another issue we had where if you called the DR the system would end up using up all the available call channels for a single call.

I'm sorry if this doesn't help at all, but thought why not.

Michael
 
Thank you for the reply. I tried this just now, i put our public ip on the first field, on the second one i changed it to use the local route, setting to the public ip kills the service, i think because its a local SBC. I'll run some tests and see what happens.
 
Sorry i should have been clearer - I had to change them both to the SIP IP address instead of the IA IP address. So they are both set to WAN IP addresses.

I should have asked before - do you have this on premise?

Are you just using the one Wan connection for the internet?
 
The 3CX system and the SBC are onsite. When changing the IP contact and and connection fields to either the WAN IP or the local IP it killed the phone service. I specified the WAN IP on the "Put public IP in SIP VIA Header" and the phone service works but we are having the same issue.
 
Fair enough.

do you get the same issue when calling from an internal extension?

it's already been requested You could try setting different codecs for external calls. I've got it set as below:

1598613811297.png
you could try switching and testing with different ones?

Good luck!
 
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