> 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.
I've been successful at using a pl2303 serial adapter and have been using
it for some time:
Bus 002 Device 004: ID 0557:2008 ATEN International Co., Ltd UC-232A
Serial Port [pl2303]
I don't think I've needed anything other than RX/TX and ground but I can
verify if the other lines actually work.
I do have 2 other USB to serial adapters:
Bus 004 Device 002: ID 050d:0109 Belkin Components F5U109/F5U409 PDA Adapter
Bus 004 Device 003: ID 050d:0109 Belkin Components F5U109/F5U409 PDA Adapter
Both of these also work flawlessly and much to my surprise were able to
drive reliably the X10 firecracker unit which runs by toggling the DTR and
RTS lines.
I would recommend that if you use more than 1 USB to serial adapter that
you make a udev entry for it.
For example I created a file called /etc/udev/rules.d/10-local.rules and
put the following line in:
BUS=="usb",
SYSFS{serial}=="1234567",KERNEL=="ttyUSB*",SYMLINK+="x10",GROUP="uucp"
What this does is creates a link from /dev/x10 pointing to whatever device
the usb to serial adapter with serial number 1234567 is actually defined
as (eg /dev/ttyUSB0, /dev/ttyUSB1 etc)
Jeff
