David Empson wrote:

Thanks for the pointer. I'll add that you also need to know a few other
things (some of which I don't know :-() to interpret it very well.
Apple's "help" on it is sure worthless, doing little more than echo what
is on the screen anyway (I can guess that the column labelled "rate"
might be a rate). For example, the help doesn't even tell me the units
of the rate. I see that my two systems connected at the moment have
rates of 54, but darned if I know 54 what.

Likewise, I don't know whether a signal of -55 is decent or not. A noise
of -90 or -95 sounds pretty bad, but since I don't notice any obvious
problems with the system, I suppose it must not be. Perhaps that minus
sign is important and larger magnitude negative numbers are better.
Still, I don't have much clue what kinds of numbers are decent,
marginal, excellent, whatever.