not sure if anyone is still looking at this thread, but my original problem has returned. After performing the base station reset last August it all worked OK until this week. Now, we are back to the old problem of the phone appearing to be connected to the base station but not receiving any calls and when I try to dial out I just get a series of horizontal lines on the screen.
I have emailed Siemens twice this week but so far no reply. Either they have got their crack team of technicians on the case and are working hard to find a solution or, they can't be arsed to reply because they haven't got a bloody clue.
Most likely option 2!