No sound on internal/external calls

[KleiDav]

Hello

We have a strange problem at customer site.

Since more than 1 year, they are using 3CX with 9 phones (Yealink T42S)
They never had big issues.

Since last week, one of the T42S started to have no sound anymore.
It rings, but when user pickup, they hear nothing, and the other side hear nothing also.
Even for internal calls, nor on the handset nor on the speaker.

So we took another T42S that was working from another user (that is on holiday) and gave it to that user, without even moving the extensions (just moving the phone, no change in the configuration)
Working !
We thought the problem was the phone...

One week later, the same user calls to say that again no sound on her phone, the phone we took from the other user and that was always working since !
And yes when we call the phone, no sound...
Asked the user to use another network cable, same problem, connect to another network wall plug (that is working fine with other phones), same problem, no sound.
All the other phones are working.

I don't know what's hapening.

 

[Saqqara]

Could be a simple case of a faulty phone.

Have you tried replacing it.

 

[KleiDav]

A

Could be a simple case of a faulty phone.

Have you tried replacing it.

Thanks.
As written, we replaced the phone by another phone that was working. And 1 week after, the replacing phone also stopped to work.

 

[leejor]

What is the setup? Phones on the same LAN as the server? Using STUN, using SBC? Does this happen only on outside calls, or also extension to extension? All Firewall checker passes?

 

[KleiDav]

What is the setup? Phones on the same LAN as the server? Using STUN, using SBC? Does this happen only on outside calls, or also extension to extension? All Firewall checker passes?

Phones on the same LAN as the server
No STUN, no SBC
Happens an ALL calls (internal / external)
Firewall OK (all the other phones have no problem)

What's strange is that it happened already 2 times in 2 weeks on 2 different phones.
Maybe it's a series of Yealink phones that will die one after the other? They are about 1 year old...

 

[complex1]

Please reset the faulty phone(s) to factory default by press OK button for >10 sec., then re-provision the phone(s) and try again.

Hope this will help.

 

[leejor]

It is only that one extension (number) that has the issue, but two sets have been tried?

 

[YiannisH_3CX]

Hello @KleiDav

Try calling the echo extension of the PBX (*777 or similar) and see if you can hear your own voice back. If yes that means that the communication between the phone and the PBX is OK. If you have no audio then that means that either the signalling with the PBX is not OK or something in the network is misbehaving. A packet capture can help you make sense of the issue as you can see the communication between the PBX and the phone and listen to the audio streams to determine is audio is transmitted or not.