The first thing I'd be suspicious of is the cable to the Palm. Some
vendors provide a different serial connector for the new (Tungsten &
Zire 71) devices than for older devices. The specification is the
same, but there seems to be a small difference on the real devices
that leads to poor connections between connectors designed for old
devices and actual new devices. The best connectors have a tab that
runs a ways up the back of the T3 in order to stabilize everything.
Try several different cables and see if there is any difference
among them.
The new devices require a proper ID resistor in the serial
connector. Cables with the wrong ID ("Y" cables in particular) can
work with old Palms, but go wonky with a T3.
The sensor device may be sensitive to the timing of signals sent to
it. This is what handshaking is supposed to take care of, but some
devices are just deaf some of the time. They are dependent upon the
sender leaving some time between characters, or between command
sequences. The T3 is a very fast device, and it may be overrunning
the performance of the sensor. While the PC is fast, it has many
other things going on, and thus may not actually drive the serial
connection at the highest speed.
I've had reports that my SerialFix extension corrected data
integrity to serial devices. The only way I can figure that this
could be true is that there must be some buffer management problems
in the standard serial handler code.
If the program works on other Palm devices, but not on the T3, then
it is worth trying the SerialFix extension. It is available at
http://www.handango.com/PlatformProductDetail.jsp?&productId=64193
SerialFix bypasses the requirement for CTS or cable ID handshake
signals. This allows usage of three wire serial connections and
cables that do not provide the proper device ID, such as "Y" cables.
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