Turning the power off certainly does the job but that's not so useful in all
other respects I guess.

I have no problem getting the dial tone simulation to be like the real BT
tone but my preference would be to be able to monitor what's going on with
the "actual" line - say line is out of order or a BT message is missed (such
as "please try again") or the BT howler tone if line is left off hook for
too long, etc.

As you say, it may not be possible as there are 2 separate circuits involved
but I thought I saw somewhere that it could be done...

Cheers from Mike