I have significant noise on my phones, if I call out or receive calls frequently the call can be started and in the middle of conversation the remote party is gone (dead line). In other cases the call randomly disconnects to dial tone.
Yesterday I tried to call my voice machine on the line with my cell phone and got a 'network unavailable' message.
I tried just now to call the 1800VERIZON number for help but can't get through the menu because the line drops.
Because it's random, it's hard for me to test this at the external NID. I can call someone for a long time, other times it drops the call in a few minutes. It seems to be random. There is also quite a bit of noise on the line.
I've tried removing phones to just one phone and turning off all sources of radio noise I can imagine (light dimmers, CFL lamps, etc) and it doesn't help.