I could not find this in the archives.
I am served by Centurylink in central North Carolina.
Some time (a year or so) after moving to a new address and porting my number from BellSouth, my phones began continuing to ring for a short interval after a call was answered.
The scenario: The multiple phones ring. I answer (off-hook). On the answered phone I can hear the power ring signal, and the unanswered phones continue to ring for perhaps one second, probably finishing the ring cycle. Then all is apparently normal.
There are 4 2-line phones (3 AT&T model 822 electronic and a Sony, not2500 sets) and a 1-line cordless, 3 with ringers turned on, and a really old but still working fine Code-a-phone 2530 answering machine connected. Possibly related, I have 2 lines, the second of which goes to the 4 2-line phones, but only one of the 4 second-line ringers is on. The problem occurs on the second line as well.
We had a service call, and the tech said he even changed the switch line card, I think. It did not fix the problem.
Ideas? I'm hoping I can tell the tech where to look.