VOIP call goes silent after approx 15mins

[#1]

Over the past couple of months a new issue has occured with VOIP calls and I haven't managed to solve it yet. I'd appreciate it if anyone can help.

When I make a call to a BT landline after 15 minutes and approx 23 seconds the call goes silent but it's still connected. The person i'm talking to can't hear me and I have to hang up and re-dial.

This seems to have occurred in the past couple of months. It was fine before this.

I am using a N300IP ATA with A&A Voip.

I am using the settings recommended by A&A.

Plusnet firewall is turned off in my account.

I have FTTP 300 and I am using the Plusnet Hub with default settings.

The firewall is enabled on the Hub and I have setup broad firewall rules to allow a range of VOIP ports with UDP.

I have set the voip registration time to 30 seconds to try and avoid it.

Strangely, the first time I call it does this, when I redial it goes past 15 minutes without issue.

(unsure if this is related but the person I am calling has a landline and ADSL, which is the only thing available at their exchange. Their line is also noisy. I don't think they have digital voice.)

Anyone have any ideas?

[#2]

Have you raised this with A&A support, they may be able to suggest some config changes

“How to troubleshoot automatic call drops on VoIP phones?
You should measure the call time when a call drops to troubleshoot abrupt calls:

If the calls have random call lengths, then:
Upgrade to the latest firmware of networking devices.
Go to router settings and increase UDP Timeout lengths.
If the calls have specific lengths, then:
Call your ISP or phone service provider to extend the call duration or remove the call timer altogether."
From here
https://krispcall.com/blog/fix-voip-phones-call-dropping-issue/

[#3]

Is it only the same calling party you get the issue? If their landline phone is noisy they should get the issue looked at.

A couple of things to try

Do you get the issue if you use a softphone installed on a smart phone? You would need to remove any port forwarding rule for this or redirect them to the smart Phone IP Address / Device name.

Try using mobile data (if your data limit allows).

To my knowledge there is not a setting to define UDP timeouts on any plusnet supplied Hub.

[#4]

It seems like it might be just the landline I am calling and after a visit from an engineer today (who found water in the box at the top of the pole) that line might finally be fixed and clear. I will give it a few days for the ADSL to recover and then will call it.

I looked at the AA call logs and it indicates it's outbound and started around 8th October which kind of lines up with the landline I am calling getting noiser and noiser.

Also as a test I called my mobile and that went past 15 minutes without issue.

[#5]

I got another disconnection a few days back and this time the Hub2 had a message in the log that said the N300IP had disconnected.

I've replaced the ethernet cable to it and and the last call lasted beyond 15mins.   I think it's fixed now.