[packetwire_59]

Hi Folks,
I am just putting this out there to see if anyone has had any type of similar issue. I can't verify exactly where the problem exists, so there is nothing saying for certain it is an issue with 3CX (to be honest it is most likely not). Here is my client's configuration (at a very high level):

PSTN Lines (Provided by Shaw Communications - Cable TV provider) --> Sangoma A200 4-PORT FXO Card --> 3CX --> 5 GrandStream IP Handsets
(The Sangoma is running NBE and exists on the same box as 3CX)

The issue that they are experiencing is intermittent audio cut-out on outside calls. The remote party can hear the local party fine, however the remote party audio cuts out (as if a mute button is being pressed) on the local set. This happens very often in the span of single call. I have ran through every log file for both Sangoma and 3CX and all looks ok, but the client has gotten so frustrated with this behavior that they have pulled the analog lines from the 3CX/Sangoma box and connected up their old phones.

Has anyone seen this before? Can someone point me in the right direction before my client throws me off a bridge ?

[leejor]

Confirm that it isn't a provider issue. Try an analogue set on a couple of the lines.
Try Wireshark, it may pinpoint where, if it is a network problem, it's occurring.
Be sure that it isn't a device on the network (switch/router) that is causing the problem. Swap out devices if necessary.

[packetwire_59]

Thanks for the reply. The network is flat, all devices connected to the same switch. We have tried multiple switch ports, no change in behavior. The client is currently using a couple of the analog lines now, as they pulled them out of the gateway and they work fine. I will setup a wireshark capture next, but i was worried that it wouldn't show much as NBE and 3CX coexist on the same box. I think we have isolated it to either communication between 3CX and NBE or NBE and the PSTN, as internal extension to extension calls are fine. We are going to try moving the card and software to a new server tomorrow, hopefully the issue has to do with the server hardware

[leejor]

Perhaps a gateway firmware (or even hardware) issue? I've seen that happen before.

[savagesystems]

I am having this exact same issue but with a Patton 4114 interface. I'm checking now to try a firmware upgrade but not sure what the cause of this either and have asked the provider to come and check the lines. Have you reached any resolution?

[efounco]

Yes, make sure you have the latest firmware for your devices. We use Patton 4960s and they came installed with firmware that was ~3 years old. Nothing but problems (audio drop outs, dropped calls, etc.) until we upgraded...

[packetwire_59]

So we updated all the firmware, Sangoma sent us out a new card and modules, we split off the 3CX server and NBE gateway onto two seperate boxes and we are still experiencing the same issues. I will be attempting to redirect calls to a VoIP provider next and verify whether the client can replicate the issue. I am really starting to think it may be an issue with the provider, even though we have had them out to check.

Has anyone here seen issues similar to this when using FXO lines from a cable provider? (i.e. Coax to the premise).

Thx.

[packetwire_59]

Just thought I would give this thread a bump...and an update. We are still experiencing this issue. I transitioned outgoing calling to a VoIP provider and the problem disappeared. We then coordinated the installation of another regular PSTN line through a alternate provider and unfortunately incoming calls on this line also experience the issue. Since we have changed out hardware, updated software and now have different lines I'm not sure what to do at this point...

A new issue that also has popped up is the cutoff of the beginning (first 10 seconds) of vm messages...Arghh .

Are there any resellers/support folks in or around the Saskatchewan, Canada area that can possibly help? I'm certain that the client is shopping around at this point and is getting ready to pull the plug...

[complex1]

I know this give you not a solution, but why you don’t try first a SPA3102, one port FXO gateway, to check the connection between your PSTN line and 3CX.
A SPA3102 is not expensive and it is a very good gateway.
If this works then you can concentrate on the Sangoma.

[packetwire_59]

We were looking at purchasing a Grandstream GXW4104 to replace the Sangoma. If it works, then great, if not we are only out a couple hundred bucks. The funny thing is it works with an analog phone attached without issue.

[Patrice]

Hello,

Are you using a multi-core amd CPU or a virtualized system on the 3cx host ?

Because the audio problems can be linked with CPU timers.
You can find more informations in the links below.

http://www.3cx.com/blog/docs/voice-qual ... rv-vmware/
http://support.microsoft.com/kb/938448

Regards,

Patrice

[packetwire_59]

We started off using a combined server (I use the term "server" loosely) running both 3CX and Sangoma NBE. As a troubleshooting measure we separated these two systems - now the 3CX server runs in a Hyper-V guest and the Sangoma hardware and NBE run on a physical box. All calls internally (extension to extension) are fine, no cut-out or errors and calls outbound through VoIP provider were also fine. The 3CX virtualized guest runs Windows Server 2008 so not sure if the links below apply (they reference Server 2K3).

[cfive]

I'm one province east ;-).

When the audio is bad - is it all there (but broken), or are there actually bits missing? i.e. a long word like supercalafragalisticexpialidocious - is it all there but with interruptions, or are there parts missing?

I may know of a grandstream port gateway that is very lightly used that we could line you up with - but it was a take-out replaced by a Patton 4114 because it wasn't ideal. The Patton (and their support) are ideal.

I haven't any experience with the Sangoma.

A couple of other far out things .. broadcom nic(s) in the host box? Any A/V product on either the host or the 3cx VM?

[packetwire_59]

There are actually bits missing - almost as if someone is pressing mute mid-word or sentence. No AV running on either, both are "vanilla" installs (with recent patches and updates). May be interested in the port gateway even just as a interim test, please pm with the details.

Thanks,
Rick