Frequently Asked Question

Because each LAN is managed differently, I can only make recommendation based on best practices.

• The likely reason this is taking place is because either someone or a VOIP/SIP app is querying your LAN.
  
• the source causing the ringing could be using the Room setting combined with the device# of the targeted monitor or simply using the VOIP settings within the LAN - most possibly using the WiFi if enabled.
  

The above gives an brief explanation as to the why this is occurring.

Now, how to best prevent such issues from taking place is based on your network design. I recommend to track from your network logs the source IP of this disruption and to simply block it from passing the commend causing the ringing... In order words, you restrict the originating IP address from calling your destination device (here the monitor based on it's IP address)...

This is a best practice and going in further details is not much possible as every network is somewhat different but the task remain the same.

Using a network monitoring tool or a network sniffer to track down the source is what I would do. If this is something that is just beginning to happen, it could be because someone  downloaded a software on the LAN side that acts as a dialer (the party downloading the app may  not be aware) unless that person is trying all sorts of combination using that said app.