newly purchased router when connected doesn't work
incidently the phones quit working also.
Everything is working otherwise.
Hmm doesn't sound like it has anything to do with filters. They have been working for years according to the OP
Here is what we don't know;
Where is the existing working router and how are things connected to it.
When the new router is plugged in, where is it being plugged in? Replacing the old router?
Are these VoIP phones or a single phone number connected to multiple analog phones?
Is the old router actually a combo unit of modem and router which is why Gutsman0X says he doesn't know about a modem?
Very possible the new router is being plugged into the filtered phone line thereby causing a short which explains the phone outage.