If you have a modular phone with no batteries, just go outside the house and plug it into the modular jacks in the gray plastic box below where your phone line comes in from the ally. If it is underground, it often comes up out of a black plastic pipe near the other meters and then goes to a ghray plastic box.
open it with needle nose pliers since it is a strange bolt and unplug the modular plugs inside one at a time andf see if you get a dial tone.
No dial tone at that point indicates it is a CT problem. The box is called the “demarc” and your side goes into the house and their side goes to the ally or nearest junction box.
If you live in an apt, the wiring is in a phone closet which usually has a bronze key box outside it with a key locked inside for the telco workers to access it.