No sound in SIP intercom anymore

[David_K]

Hello

Customer has a Behnke SIP intercom placed in the street, so they can open the door remotely from another phone.

Configured it 2-3 months ago, had not problems

2 weeks ago customer called to say they can't hear the people in the street anymore (from the street you can hear the office)

A clue what could it be?

Rebooted the intercom several times, firmware to latest version.
What's strange is that it was working before.

The only thing we've changed some weeks ago is that before the push of the button on the intercom was calling a ring group, but customer wanted to have a different ring tone when intercom was calling, so I've changed to the intercom now calling a call queue instead of the ring group.
But not sure that this could impact anything?

 

[JohnS_3CX]

Hi David,

You could try making it call the ring group to see if it makes any difference, but I don't expect there would be any.. The problem is likely the fact that no audio is being sent

Since this is not a supported device we cannot really comment on it, but if I was you I would look into the following:

1. How does it register to the PBX: LAN / SBC / STUN ?
2. What IPs do you see in the SIP messages SDP section?
3. Is there any RTP traffic being sent out from the door phone?

If you look at these 3 points in this order, you will eventually track down exactly what played out during the failure.




PS: If you had shared more info as from here, we might have been able to provide you with more insights

 

[David_K]

1. SBC

2. Where can I see that?

3. How can I check? I suppose that yes because it was working...

 

[JohnS_3CX]

Hi David,

You will need to first capture the traffic using your firewall (if it allows this) or find another method to run a packet capture on the doorphone device itself. Then you will need to analyze the traffic in Wireshark, which requires some knowledge of SIP and networking.

If you want to give it a go, this 3CX Academy module may come in handy. Just keep in mind that the packet capture feature built into 3CX will not be useful to you - you need to directly capture the traffic the doorphone sends to the SBC.

Alternatively if you think this is "above your paygrade" so to speak, then give one of our 3CX Partners a go. They will be able to assist you in troubleshooting. If you do not already have a 3CX Partner, you can quickly find one close to you from here: https://www.3cx.com/ordering/find-reseller/