Re: usb to serial
On Sun, 4 May 2008, Celejar shared this with us all:
>--} On Sun, 4 May 2008 13:49:24 +1000 (EST)
>--} Daniel Dalton <daniel.dalton@iinet.net.au> wrote:
>--}
>--} > I'm a blind debian user and therefore use a braille display.
>--} > So I need to connect it somehow.
>--} > The display is a piece of hardware that is usually connect with a
> serial --} > cable, but since my new box only has a usb available, no
> serial I must use --} > usb to serial.
>--}
>--} I have a similar situation with my laptop, which doesn't have 'legacy'
>--} ports such as serial, so I use USB to serial adaptors for my serial
>--} equipment.
>--}
>--} > So does anyone know of the following:
>--} >
>--} > - a supported usb to serial cable for linux that works with the
> kernel? --}
>--} These adaptors are 'smart', i.e. they contain electronics to do the
>--} conversion, so as with hardware generally with linux, what counts is
>--} the chipset. I believe that many of these devices use the Prolific
>--} PL2303 chipset, which shows up with 'lsusb', at least in my case, as
>--} "ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port". This
>--} chipset has kernel support via the pl2303 driver. I have another
>--} adaptor whose ID apparently isn't in the database; nothing shows up
>--} other than the numerical ID. It is also grabbed by pl2303 (although
>--} IIANM, that wasn't the case several months ago, when I first acquired
>--} it), but it doesn't seem to be working properly, as opposed to the
>--} Prolific one, which works fine.
>--}
>--} I purchased both my adaptors on Ebay. They are virtually identical in
>--} appearance, except for color; both have attractive silver cables
>--} sheathed in clear plastic, but the Prolific has black plastic covering
>--} the two cable ends (serial and USB), while the other has translucent
>--} green. This may not help you.
>--}
>--} I originally bought these adaptors to use with serial modems, but I was
>--} never able to get them to work properly, and I never figured out why.
>--} I'm currently using the Prolific to manage a headless box via a serial
>--} (null modem) cable, and it works perfectly. The other one is not
>--} working properly, as above.
>--}
>--} These things start at about $5 (USD), including shipping (to the USA)
>--} on Ebay. If you search there for 'usb serial', the first bunch of hits
>--} seem to be the sort of units that I bought. There are both green
>--} headed ones, as well as black headed ones, but I don't know if the
>--} color is a reliable indicator of the chipset.
>--}
>--} > (If so could you please provide a model number or brand?) Or even
> better --} > if you know where I can get one of these from?
>--} > Perhaps you could show me an add on ebay?
>--} > (I had a look, but don't really understand the info and I am having
>--} > trouble using my computer obviously.)
>--} > - If the kernel supports it will a software daemon (brltty) support
> it? --}
>--} I don't know brltty, but I'd say almost certainly yes. I'm no kernel /
>--} hardware expert, but basically, the kernel driver creates a virtual
>--} serial port, which should appear identical to an actual one to
>--} userspace.
>--}
>--} Good luck!
>--}
>--} > Daniel Dalton
>--}
>--} Celejar
I have used a USB to RS232 Cable for some years with Linux Debian, coupled to
an external dialup modem and it worked a treat without fault. It was not a
fancy brand named cable, just one that I picked up in a computer shop, and
was about 1 metre long I think? I haven't used it with testing for about 3
months because I now use satellite. So something may have changed since then?
HTH
Charlie
--
Registered Linux User:- 329524
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