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Re: How Do You Know If It Works In Linux?



On Wed, Oct 01, 2003 at 06:40:07AM +0800, csj wrote:
> At Tue, 30 Sep 2003 14:53:43 +0100, Pigeon wrote:
> > A point about USB and modems is that USB is fast enough to make it
> > possible to implement an external winmodem. It may well be
> > safer/cheaper to use an RS232 modem with an RS232-to-USB converter.
> > (having found one of those that's supported in Linux :-) )
> 
> Interesting.  But is the probability of a RS232-to-USB converter
> being Linux-compatible higher than the probability of a USB modem
> being compatible?

If the USB modem is an external winmodem, then definitely yes, as all
you have to do is blurge data in and out without trying to replicate a
complex closed-source DSP algorithm.

> Is it just a dumb cable with a serial port
> connector on one end and a USB connector on the other?  Or is
> there some fancy electronics involved (e.g. a chip embedded on
> the serial side)?

The latter. USB and RS232 are way different and there is no chance of
building a simple passive converter.

> How would Linux recognize it?  What would be
> the modem port?

ISTR from http://www.ftdi.com - who make USB-to-some-easier-format
conversion chips - the answer is 'something straightforward'. Long
time since I looked at the site though. Chances are it would be
recognised as a USB device and you'd need to symlink it to /dev/modem.
It might depend on who made the conversion chip to some extent.

-- 
Pigeon

Be kind to pigeons
Get my GPG key here: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x21C61F7F

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