|Re: HP 48GII and 49G+|
Message #10 Posted by James M. Prange on 29 Apr 2004, 8:05 a.m.,
in response to message #4 by Ron Ross
Actually, the 48 series and 49G don't comply with RS-232 either. Their
output is about +/- 3.5V, possibly as low as +/-3.0V; see:
http://www.hpcalc.org/details.php?id=4741. To meet RS-232, the
transmitted signal would have to be at least +/-5.0V. But RS-232
specifies input levels of +/-3.0V, and the calculators are usually
used with short cables with little signal loss, so it's probably fair
to say that they're "RS-232 compatible". I think the manuals never
actually claim this, calling it a "serial port" instead. The only
problems I recall reading about were with some Macs, which I expect
were actually equipped with RS-422 ports instead of RS-232 ports.
My understanding is that the 48gII signal level without the special
cable is practically identical to the 48 series and 49G, so if you
supply your own non-amplifying cable, you can probably use it wherever
the older calculators would work.
Regarding the lack of an upgradable flash ROM, yes, it seems foolish
to expect to get a reasonably bug-free ROM, especially in a hurry with
practically the same complicated ROM used in the 49 series and the
processor emulated. What were they thinking?
And it has less RAM available than the 48 series, and no expansion
card capability. Too expensive for a "low-cost" model in my opinion. I
wonder who would buy it; it's hard for me to imagine the niche in the
market that it fits into. But who knows? I'm no marketing specialist.
Still having an RS-232 compatible serial port does sound good though.
The USB port on the 49g+ is nice, but I'd much rather they'd added a
USB port and kept the RS-232 compatible port instead of replacing it.
Edited: 29 Apr 2004, 8:42 a.m.