CPL and Phone?

You can connect a DECT phone to the operator's terminal if they offer internet telephony.
But it works through a number starting with 09: it's no longer a phone accessible directly via the internet. You need an operator.
In the end, what they call internet telephony is going through an internet gateway. But it always links back to the analog telephone network.
They have no interest in you connecting directly to the internet on your own because they would lose a subscription...

Okay, thank you all for your responses and your quickness!

Hello,

The CPL is used to build a computer network.
Therefore, you need to connect an IP phone using the SIP protocol, for example, and subscribe to a provider if you want access to the traditional telephone network.

Here are a few providers: http://www.sed-p.net/Fournisseur-de-voix-sur-IP-Proxy.html

However, for purely internet telephony (calls between SIP clients), the provider is not necessary. It is indeed possible to call a SIP phone (or client software) directly over the internet using the IP address (or through dyndns).

With SIP, there is no need for an operator anymore.

Best regards,