I never thought about phone numbers but just did read and it's kind of complicated.
Wikipedia: "German telephone numbers have no fixed length for area code and subscriber number (an open numbering plan)."
In Germany we have the trunk prefix VAZ "0".
That tells the phone to call outside and connect to the telephone exchange for long distance.
Looks like in the US most of the time it is "9".
With the phones here in Germany that is/was build into the phones and if you do not dial the city prefix
that always starts with "0" you are connected to the city telephone exchange.
That's the reason something like just 3267 works in the same city.
With VoIP it still works because the provider does automatically but your city prefix in front of the dialed number.
But it only works if you are calling from the city where your phone is registered. If you move to another city and plug it in there it would not work.
I just found out you can get the 032 prefix so you don't need to change your number if you move.
Then there is the international VAZ "00" and you are conected to the foreign countries telephone exchange.
"+" in front of the number instead of 00 is just for cellphones.
Wikipedia: When making a call, the system then automatically converts the plus sign to the correct international prefix, depending on where the phone
is being used, which enables callers to use the same stored number when calling from either their own country or any other.
The idea was a expression that calls outside if a number starts with "0".
But i guess the problem will be the same (outbound routes catching calls to my extension) because incoming calls also start with "0"?
I wonder it did work in the old installation