Hi Steve, sorry if my explanations are clouding the issue.
The previous attached call log was the last time an incoming call registered and worked. Since that date , incoming calls no longer register in the call log , and nor do they get answered by the Obi and sent to the connected house phones. (a temporary phone in parallel with Obi Line in , does ring as you would expect on an inbound call, the ring tone/cadence sounds normal enough.. unsure why the Obi doesn't hear or recognise it as a 'ring' though.)
Obi is still under Wrty and Premium Tech support though to May 2018.
*Edit: Hmm.. plugging that temporary phone into the line in cable of the Obi , has no dialtone.. plugging same phone into 'street' side of the ADSL filter/splitter has dialtone. Thinking now i DO have a wiring or filter issue.
I will need to dig a little deeper.
*Update: Found my issue... not the Obi afterall. it appears that the house alarm 'dialler' has a stuck relay that is not passing the phone line through to the Obi. I have put a bypass loop in, until i can get the alarm panel looked at.