digital home phone doesn't detect incoming call

Hi everyone !

I moved to Canada (Montreal) from France.
I brought 2 home phones with me.

The first one is a basic AEG wired and powered bu the phone line. Works perfectly.

The other one is better for me because it's wireless and the base contains a message box: Siemens Gigaset 2015.

The problem is, it doesn't detect an incoming call on the line !
I can call with it, no problem - I even can here the "opened line" when pressing the green button.
The ring works because I've got a "lost" button on the base to call the handset.

I'm sure it's a problem of "line call detection" because I've configured the answering and when you call, there's no auto answer.
The phone is behind an internet filter, but the other too. I tried to move it to another place at home (keeping the filter) it's the same.
It's powered by an adapter but I use a big transformer to give it the 230v needed.

Then I start to think about a line tension compatibility while ringing .... ?
Someone knows if there are technical differences between European and Nord American phone lines ?

Thanks a lot in advance for your answers !
(hope I'm not posting it in the wrong category...)

please, no idea ?
even something I could try to see what happens ...

Thanks !

According to ETSI EN300001, European public switched telphone networks are already utilizing a wide range of ringing signals
from 16 to 55 Hz and 25 to 120 V. Your telephones should be expected to work with any of these. I can hardly imagine, that
canadian networks are working even outside this range.

Telephone ringing in Canadian cities is 90VAC/20Hz superimposed on the 50V battery.
The cadence is 2 seconds on and 4 seconds off.

May be connections are swapped some where in the RJ11 or RJ45 jack whichever is used....Cheers

Thanks a lot FvM and Audioguru for your answers !
Ok so it means there's actually a big tolerance and it's supposed to work...

pranam77 : it cannot be the cable (rj11) because there are only 2 wires and I can give a call with it (even receive if I pick up the phone during a conversation on the line)