Re: How to use an USB<->serial adapter?

From: Boszormenyi Zoltan
Date: Fri Aug 22 2003 - 02:52:32 EST


Greg KH wrote:
On Thu, Aug 21, 2003 at 02:44:18PM +0200, Boszormenyi Zoltan wrote:

Hi,

I am experimenting with a Prolific USB<->RS232 adaptor. We have
in-house developments that need serial communication and there
are more and more mainboards that provide only one RS232 connector.
(We would need more in one machine...)
So we decided to try an usb-serial converter. The one we bought
was happily recognized by a RedHat 9 system but I couldn't get
two-way communication over this converter.


Which kernel version are you using?

RH9 errata kernel 2.4.20-19.9, I also tried 2.6.0-test3-mm3.
On a sidenote, I also tried its driver on W98SE, WinXP.
Same result with the MinGW compiled test programs.

I didn't run your test programs, but are you sure you got the hardware
flow control settings correct? How about testing the device with

Hmm, how comes the same settings *work* on real 16550?
Even under Win*, with the MinGW compiled testprograms...

minicom, as that is a program that is known to work properly with these
devices (along with lots of other ones, but that's a good place to
start.)

I tried it now, thanks. Same thing happens. I set up two different
minirc, /etc/minirc.dfl using /dev/ttyS0 and /etc/minirc.usb
for /dev/ttyUSB0. In one terminal, I typed 'minicom', in another
'minicom usb'. In the 'minicom usb' what I type, appears in the
other window, but keys typed in the 'minicom' do not appear in
'minicom usb'.

I am starting to be convinced that it is a hardware flaw.
I will try to replace it.

setserial produces an error:

# setserial /dev/ttyUSB0
Cannot get serial info: Invalid argument


Yes, setserial does not work with the majority of the usb-serial
drivers, patches gladly accepted to fix this :)

I wasn't prepared to this answer. ;-)


thanks,

greg k-h

--
Best regards,
Zoltán Böszörményi

---------------------
What did Hussein say about his knife?
One in Bush worth two in the hand.

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