[Nut-upsuser] Problems in communication with Mustek PowerMust 1060 LCD

[Daniele Pezzini]

Since we get valid replies (when we get any), I'm assuming we're
speaking the right 'dialect' and using the right (or an almost right)
serial-over-USB implementation.
Apparently, after a successful query, it takes the device ~10 seconds
to reply (see how, when trying to read the reply to the 'QS' query at
~23s, we actually get the reply -the one starting with a '#'- to the
'F' query sent at ~13s, and when trying to read the reply to the
latter, we actually get the reply to a 'QS' query, probably the one
sent at ~3s).
If that's really the case, I'm not sure there's much we can do... you
could try to ease the pace of the polling to match the time the device
needs to reply, so that every new poll will get the reply to the last
one (e.g. setting 'pollinterval', or 'i' arg, to 10 seconds or
something like that).
Also, you could try another serial-over-USB subdriver (namely the
'phoenix' one, instead of the default 'cypress' one, but feel free to
try also the other ones).
Finally, if you end up with a usable setup and if the device still
needs 10s to answer our queries, consider using the 'norating' and
'novendor' flags, since it's not likely that we get any reply to those
queries in time to process them (and then they could even be seen as
'pollution' to the next status queries).