Delay in call response on hosted 3CX - Fanvil V64

[Battistini SRL - Matteo]

Good morning,

On a 3CX hosted environment with a Pro license, I've set up a PBX with a digital receptionist (IVR) that routes calls to a ring group with two extensions—two Fanvil V64 phones, each connected as an SBC phone.

The issue is this: When a call comes in and the customer answers, she experiences 3-5 seconds of silence (mute) at first. She tries saying "Hello? Can you hear me? Hello? Hello?" Then, the call proceeds normally with clear audio and continues without issues.

This doesn't happen on every call—for example, when I call the customer from my 3CX PBX, she hears me immediately upon answering. It only occurs with certain calls, in a way that's still undefined.

Could you help with what checks to perform first?

P.S.: The exact same issue happens on another customer's PBX, also with physical IP Fanvil V64 phones, but that second PBX has a Free license.


Best regards,
Matteo

 

[TheodorosG_3CX]

So the dealy is on the ip phone correct?
Using the web client the same apply?

 

[Battistini SRL - Matteo]

Yes, the delay is on the IP phone. I haven't had a chance to test it on the web client because this customer only uses IP phones to answer and then transfers calls to external smartphones 3cx apps.

 

[TheodorosG_3CX]

You can try to verify with the web client.
Also please check how many BLF keys have been assigned to the device.

 

[Battistini SRL - Matteo]

The BLFs configured on the phones are 9 on each of the two phones in the PRO version.

On the second PBX in the free version, the phone has 3 BLFs.

I'll try to convince one of the two customers to respond via the web app to check if the problem occurs there too.

 

[NikosT_3CX]

@Battistini SRL - Matteo out of curiocity, if you reboot the phones to clear their local cache, do you still have this delay after ?

 

[Battistini SRL - Matteo]

@Battistini SRL - Matteo out of curiocity, if you reboot the phones to clear their local cache, do you still have this delay after ?

Yes, the tests that have been done so far are:

• Rebooting the phones,
• Updating the phone to the latest 3CX-compatible version,
• Rebooting the cloud PBX.
• Changing IP manually on the Fanvil phone tested with the company's internal DNS (windows server - domain controller)
• Changing IP manually on the Fanvil phone tested with the external DNS (Google 8.8.8.8)

 

[JTTenbrook]

Any update on this? We are experiencing the same issue with Fanvil V64s.

 

[TheodorosG_3CX]

Have you also proceeded with the new firmware releases as per blog post here?

 

[JTTenbrook]

Have you also proceeded with the new firmware releases as per blog post here?

Thanks for the reply.

There is no new firmware update available in 3CX for the V64 series. The latest is version 2.12.20 which came out in 2024.
The blog post you linked is specifically about the X series, not the V series.

 

[TheodorosG_3CX]

Have you also confirmed the BLF keys?
How many ip phones are provisioned behind the same router phone?

 

[Kevin Attard Compagno]

Are the symptoms similar to the one here: https://www.3cx.com/community/threads/answering-delay.136822/post-656404 ?

 

[JTTenbrook]

Have you also confirmed the BLF keys?
How many ip phones are provisioned behind the same router phone?

7 BLFs per phone. Each phone is acting as its own Router Phone.
I've rebooted the PBX, the firewall at the site, ISP equipment, switches, etc. No change.
Can confirm the 3CX app did not have any issues - only the Fanvil V64 phones in particular.

I tried pushing this firmware found on Fanvil's site as it explicitly mentions the call delay issue: https://fanvil.com/upload/files/20260312/1424zx8r80.pdf
Waiting to hear back from the customer as to whether this fixed the issue.

 

[JTTenbrook]

Are the symptoms similar to the one here: https://www.3cx.com/community/threads/answering-delay.136822/post-656404 ?

Similar symptoms, but these phones are only a couple of months old so I don't think it is just age-related deterioration. Rebooting them did not help.

 

[JohnS_3CX]

Hi all,

If you experience sluggishness particularly on the Fanvil V64 when used as a router phone, it is now recommended by Fanvil to contact their Support and report it.

They will investigate on a per customer basis and depending on what hardware you have they might replace it for you with a newer hardware revision.

Make sure to inform them that it is used as a router phone, and the you experience this sluggishness in response time.

 

[JTTenbrook]

Update on this after working with Fanvil support:
We found that this issue occurs whether the phones are set as router phones or have a dedicated SBC.

After sending the logs from one of the phones, Fanvil Support was able to determine that there is a bug in the 3CX-supported firmware version 2.12.20 that causes memory issues. None of the publicly available firmware versions on Fanvil's website appear to fix this issue, either. We tried 2.12.20.19, 2.12.20.36, and 2.12.24.11 in addition to 2.12.20.

Fanvil support sent me a Google Drive link with firmware version 2.12.21.3, and that firmware version did fix the problem.

Not sure what needs to happen to update the official firmware on this list but doing so would be very helpful for future installs.

Thanks

 

[Battistini SRL - Matteo]

Update on this after working with Fanvil support:
We found that this issue occurs whether the phones are set as router phones or have a dedicated SBC.

After sending the logs from one of the phones, Fanvil Support was able to determine that there is a bug in the 3CX-supported firmware version 2.12.20 that causes memory issues. None of the publicly available firmware versions on Fanvil's website appear to fix this issue, either. We tried 2.12.20.19, 2.12.20.36, and 2.12.24.11 in addition to 2.12.20.

Fanvil support sent me a Google Drive link with firmware version 2.12.21.3, and that firmware version did fix the problem.

Not sure what needs to happen to update the official firmware on this list but doing so would be very helpful for future installs.

Thanks

Hello, could you please send me the link for the firmware 2.12.21.3?

 

[AJD_Tech]

I'm also interested in the link to the firmware.

I just swapped out five V64 phones yesterday and replaced them with X4U's because of this issue as well as complaints about call volume.

For now, we've decided to no longer deploy V series phones until we can verify improvements. Right now we're just eating the cost on the V64's we've deployed...

 

[JohnS_3CX]

I'm also interested in the link to the firmware.

I just swapped out five V64 phones yesterday and replaced them with X4U's because of this issue as well as complaints about call volume.

For now, we've decided to no longer deploy V series phones until we can verify improvements. Right now we're just eating the cost on the V64's we've deployed...

See my last message above, it might interest you if you haven't contacted Fanvil already.

 

[Allen_Miller]

It appears that I've run into the same issue here. I've sent an email to Fanvil.
If someone can get me the firmware sooner i would appreciate it.
regards,
Allen