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[aprssig] PocketAPRS with Clie?

Stephen H. Smith WA8LMF2 at aol.com
Fri Feb 18 06:10:21 UTC 2005


J. Moen (K0ZXU/6) wrote on 2/17/2005, 3:41 PM:

 > I think I'm doomed here, but maybe someone else has figured this out.
 > The Clie's connection to PCs is via USB.  I have a USB to serial
 > adapter, but that adapter (I think) depends on the 5 volts that USB
 > sources like PCs usually provide.  Obviously the D7's "PC out"
 > connector has no DC.   I guess I could rig up a small battery pack to
 > provide a bit of power to the adapter, but before fooling with all
 > that, I thought I'd check the experts.

5 VDC power is the least of your problems.

USB devices fall into to two classes: "MASTERS" (controllers that assign 
a USB device it's identity) and "SLAVES" (peripherals devices that 
depend on the master to be told what to do).   SLAVE devices can only 
interface to a MASTER; not another SLAVE.  [The two different styles of 
USB connectors recognize this relationship. The wide flat "A" plug 
always faces toward a master while the beveled square "B" plug always 
faces toward a slave device.]

Normally a master would be the full-size PC.  The PDA acts as a slave to 
the PC, just like a printer, scanner, external hard drive, keychain 
flash drive, USB-to-serial "dongles", digicam, etc.  [Logically, to PDA 
sync utilties on the PC master, the PDA appears to be merely a bunch of 
flash memory in a box, not another computer. ]

Trying to connect a USB-to-serial dongle to the PDA would amount to 
connecting one slave device (the dongle) to another (the PDA) -- it 
won't work.




Stephen H. Smith             wa8lmf (at) aol.com

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