We were facing a problem before where callers would call in, asterisk reports that the call gets answered by the IVR but the caller still hears the ringing tone. When a Digium FXO module starts behaving this way, it would never work correctly again.
We finally figured out the problem when we tried moving to a commercial solution and their modules died the same way and the company did some diagnostics.
It was caused by high ring currents. The ring current is really high because we’re located a few feet away from the phone company’s phone switch.
We’ve tried using surge protectors to limit the currents but that didn’t work.
Has anyone faced the same problem with high ring currents and found a good solution to control it?