I guess I don’t know how to check this out. Maybe mu download rate is slower now if maybe recently they have substituted the system you described. I’ve had this line for 33 years. In fact, about 8 or 10 years ago the squirrels apparently chewed through the line at the pole, and it had to be replaced. I could see where the line was parted.
If you see a local phone guy ask him if you are “straight” out of the CO on copper or go through an “RT” (remote terminal) somewhere in the neighborhood.
CO batteries last forever because they are huge plus they probably have a gen.RT batteries maybe 36 hrs depending on how many people go off hook and for how long.