Okay guys, thanks.
Yes, as you've surmised, I'm only just beginning to get to grips with
this complex piece of kit and there is *much* to learn indeed. In my
defence, I have to say although I purchased this thing 5 months ago,
I've only now been able to assemble the ancilliary cables, loads,
splitters and whatnot to be able to check it out properly. All I could
do back in December was to switch it on and check for signs of life.
Now, however, things start to get rather more complicated ( but
hopefully stimulating, too).