PL2303 & gui serial status display for /dev/ttyUSB(x)?
Les
hlhowell at pacbell.net
Fri Dec 29 07:56:29 UTC 2006
On Thu, 2006-12-28 at 11:14 -0500, Bob Chiodini wrote:
> Gene,
>
> I tried a pl2303 serial to USB one and had problems. It was a radio
> shack branded device.
>
> Using FC4 at the time it looked like only every other character was
> being received by the host. Data to the device was fine. Unfortunately,
> I never resolved the problem and opted for a four port Keyspan device.
> No problems connecting through it to the same serial device.
>
> If the Garmin only has four wires, most likely the handshake is
> XON/XOFF, if any. Does the Garmin "talk" correctly via one of the "real"
> serial ports?
>
> Bob...
>
> Gene Heskett wrote:
> > Greetings;
> >
> > Trying to get roadnav to talk to my elderly Garmin 12, and because I'm out
> > of serial ports, the garmin 4 pin to db9 connector cable is plugged into
> > the db9 end of a pl2303 serial to usb adaptor. The pl2303 is recognized
> > and assigned to /dev/ttyUSB0 according to dmesg.
> >
> > I'm apparently getting zero data from the garmin and I suspect its the
> > lack at least the 7 wire protocol at the garmin side of the pl2303. I
> > believe it may even be just a 2 wire & ground setup as the garmin
> > connector is only a round 4 pin, probably with little or no flow control
> > as the garmin apparently runs at 4800 baud only.
> >
> > But, I'd like to ask here on this list: Has anyone ever made a pl2303
> > based adaptor actually work?
> >
> > The only other time I seriously tried to use this $40 gizmo was as an
> > interface translator with the rs-232 pack of a vintage coco on the other
> > end. At that time I was able to type back and forth using terminal
> > programs on both, but a known good zmodem setup on the coco failed to
> > move more than about 10 bytes of a 10k file when I had minicom attempt
> > the transfer. At the time I also suspected config/handshake problems and
> > eventually gave up, but now I think the pl2303 may be busted or
> > miss-configured, hence the request for a gui program to monitor
> > individual wire status at the db9 connector, but do it
> > using /dev/ttyUSB(x).
> >
> > Is this latter idea even possible?
> >
> > Thanks everybody.
> >
> >
>
Sorry to just butt in here, but I am a sailor and use lots of GPS
products. You will probably find that the garmin implements NMEA-183c,
which does not use XON/XOFF, but simply ends messages with Carriage
returns. You can find the commands in either the Garmin manual (if you
have it), or on line at Garmin.com. They are a pretty good company in
my experience. Their interface is really "three wire" with a power
option. Most of their older equipment used the 4 pin round plug, with
ground, +12, serial in and serial out. I don't remember the pinout, but
I also have an older 12 model wired to the radar on my boat to give
position and waypoints to the radar screen. It also makes a nice 2nd
GPS "just in case".
I am not familiar with the software you are using. Is it under GPL, or
is it a commercial product? I have been looking for a reasonably cost
effective software package to enable me to put a low cost nav station
setup on my boat.
Regards,
Les H
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