Re: Serial port & Modems (External) (fwd)

[adam@tiamat.umd.umich.edu (Adam Wilkinson)]

> 
> > >	Is there anyone on this list who uses the external serial port
> > >and connects a v.32bis modem to it?  I realize lots of you have PCMCIA
> > >modems, but I'm curious as to any who just have a plain 'ol external.
> > >
> > >	I recently got a new USR Courier "V.Everything" (28.8K) modem
> > >for my desktop (where most all of my modeming is done) and since I have
> > >a "spare" modem in the form of a Supra V.32bis FaxModem, I decided to try
> > >running it from my ThinkPad.
> > >
> > >	I runs fine when I lock it down at about 9600 baud, but at 14.4K
> > >Baud, I have some problems.  Namely, it seems to scramble an occasional
> > >character when I'm in this EMACS editor, but more seriously, prevents
> > >any meaningful file transfer at 14.4K baud (though 9600 works okay).  It
> > >produces a number of CRC errors.
> 
> > If someone has not already suggested it, remove FUELDOS.EXE
> > it fiddles with the serial port for some unknown reason.
> > I had the same problem.. removedit and I wa fine!
> > 
> > -James
> 
> 	It was suggested by one person (thanks again, by the way), but it
> did not work.  I think, under Windows at least, I'm doomed to 9600 baud
> unless a 16550 UART magically appears--I'm *really* ticked that IBM would
> scrimp on an important item like that (costs a whopping $5 more at the most)
> on such an otherwise wonderful machine.  I guess they figured everyone would
> use PCMCIA modems and not externals.
> 
> 	Which begs the question, oh you PCMCIA gurus:  Do you ever have
> any trouble using your 14.4K PCMCIA modems under windows?  Is the "serial"
> port in the PCMCIA slot fast enough to keep up with things?  I would like
> to know the answer to these things before I sink $ into one someday--and
> do you think PCMCIA would still work fine with a 28.8K modem?
> 
> 	Now maybe one can do 14.4K on an external serial under DOS, but I
> prefer Windows (or as Sean suggested--use OS/2!  Damn you Sean--you got me
> there!).
> 


Two things -- first, make sure you have the latest verion of FUELDOS, I 
understand that the newer verions do not adversely affect serial 
communicaitons. Second, the reason that almost all manufacturers, 
particularly of notebooks, use a 16450, is because that what's in Intel's 
standard support chipset. Using a 16550 would mean either somehow disbalg 
that UART, or using another support chipset -- so much for compatibility. 
IBM had a 16550 on the 700/720 because those ran on an IBM processor with 
IBM suport circuitry.

-- 
Adam Lee Wilkinson          * Just remember, no matter where you go,
adam@tiamat.umd.umich.edu   * there you are!   
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