That happens with old cordless phones. Somebody had a bright idea midway through to 2.4 and 5 Ghz range and screwed up with a panic alarm.
Just pick up a AT&T or Panasonic set of phones from Costco for $100 and be done with it. You can have a phone in every room and the police won’t gun you down while you’re sleeping.
I've been taken to task many times around here for complaining when I believed I was reading about improper police behavior. So my bona fides are in place when I say that I was impressed in this thread by how polite, concerned, safe and professional the cops have been in the reported incidents. Fair is fair.
This cordless set is a PanasonicKX-TGA101S. It has served us well over the years. Got new batteries for the handset this year. As another poster mentioned . . . it’s really time to resolve the line issue.
At the same time, if this is happening more often to more people, it gives pause. Which is to say, maybe there is a prankster on a larger scale who is intent on creating chaos by tying up emergency resources.