Profilemaker Pro Problem
Profilemaker Pro Problem
- Subject: Profilemaker Pro Problem
- From: Nick Wheeler <email@hidden>
- Date: Sun, 09 Sep 2001 13:46:15 -0400
Launie:
I finally arrived at the solution to my problem Saturday morning. A friends
phone call the previous day proved a catalyst. We weren't talking about this
particular issue but his admonishment was relevant. I'll reprint it here, it
benefits us all.
"Nick, I've been doing this long enough now to realize none of us know all
that much, that you should assume nothing, never jump to conclusions, and
thoroughly test and re-test every conclusion you do jump to." -John
Wawrzonek.
Thank you John, and thank you all for your help.
It wasn't a particularly a Profilemaker Pro problem at all although the app
may have played a role, it was a USB problem. Or put more precisely my lack
of knowledge of USB architecture.
I had the Spectroscan plugged into an unpowered USB port. Plug it in to a
powered USB hub and the problem disappeared. Why it works for a while
(sometimes months) and then fails I have absolutely no idea. But the powered
hub proved the cure.
It may be that in the really low power of a USB circuit some type of
resistance, capacitance or inductance builds up over time that ultimately
renders the circuit useless for USB communications. Why SpectroChart Lite
still worked and Profilemaker pro not I have no idea.
Spectrochart lite demands that printer emulation be turned on, Profilemaker
Pro demands that it be turned off. Maybe there is something there. Lower
baud rate less susceptible to noise?
I have heard several people mention that unreliable USB devices worked well
when plugged into a Power Book (such as Terry's setup) which is a form of
powered hub, and I'll bet that Andrew Rodney has his Spectroscan plugged
directly into the back of the G4 mothership.
My mistake was in assuming that since the device is powered (the
Spectroscan) then its USB connection is also powered. Since the Spectroscan
is really an older serial device this is probably not true - right?
Anyway I'll bet that if you search through your other cases that match this
one you will find this might be a solution.
I suspect that it makes some sense to use a powered USB hub for all USB
devices. I think it will result in greater USB communications reliability in
general. I know I sure will. There I've jumped to conclusions again!
Best wishes,
Nick Wheeler