My application is interfacing with a Daytona Analog HMP PCIe 16T board.
The intension is to log POTS phone-lines in passive mode.
Therefore each trunk channel is connected in parallel with a phone-line.

Besides passive logging of the phone-line, I am also interested in detection of some phone protocol events, i.e. on/off-ring events. It is the reception of those events that malfunction. Only sometimes ring-on/off events are received while the phone is ringing.

The ringing signal is generated by a company phone system. The ring signal is about 100 Volt top-top, with an average voltage of 0 Volt (so a pure AC-signal).
Why is not each ring signal preceeded by a ring-on and terminated with a ring-off event?

Thanks for any answer(s)
Jan Schellens