Finally, a small note: as an alternative to the repeatedly mentioned Internet technology, there is also the mobile network - i.e. 4G, which can be used as a new technology.
We are happy to give you our personal advice on this topic: do not blindly expose yourself to the goodwill of the market leader. Keep the threads in your own hands!
Then it makes perfect sense to invest in a second Internet connection. It is important that the second connection arrives on a different medium. This means that you should not use a second DSL connection if you already have a DSL connection.
"In this case, a second connection should be a coax connection, a mobile connection over 4G, or a fibre optic connection - also called Fibre.
Guideline for the required Internet bandwidth for VoIP: a telephone call requires approx. 100 kbit/s