Re: [FWD: RE: null modem cable]

Jean-Francois Messier wrote:
> Well, in order to see whether the problem is in configuring Linux for
> the serial port, can you temporarily try to connect your modem to a
> Windows PC, where you can perhaps have a better configuration of the
> serial port ? Also, some devices will auto-configure to the actual speed
> of the port. I know that a USRobotics 56K modem  was auto-configurnig
> with connected to the serial port of the PC. 
>
> Can you get the same router on a serial port working on another computer
> ? If so, this might be a port issue on your computer, or a software
> config issue. 
>
> Is your device's serial port working with some known commands and
> expected replies ? is this a console port for a straight login ? 
>
>   

Typically serial ports are defaulted to 9600 bps 8 data bits, 1 stop bit 
and no parity.  I can't see any reason to connect it to Windows, there 
isn't a different "magic" kind of easier serial port configuration used 
by Redmond.  Using a serial terminal communication program to connect to 
the port (there are lots), you can set the port to whatever 
configuration you want and try to communicate.  Google is your friend 
and you should quickly be able to find out the factory port 
configuration on the router (or whatever).

I've never played with auto-configuration devices - just devices that 
happily used 9600-8-1-N as a default.  You may have to make the cable 
support hardware protocol (CTS/RTS) as well - it is much more reliable 
than XON/XOFF in software.  I've used Minicom on Linux (and Telix on DOS 
before that) and it works fine.  Serial port logging is a good thing to 
know, echoing logs normally dumped to /var/log out a serial port to a 
serial printer or to a log capture device.

I grew up with 300 bps acoustic couplers that were the size of a case of 
beer.  I'm sure I've got a serial breakout box and a protocol analyzer 
somewhere in the basement as well.

I kind of feel like an ancient geezer right now.  Wyse terminals running 
off 8/16 port Connecttech cards allowing 8 users to run off 
character-based terminals under Pick, QNX and Xenix.  How far we've come 
in some ways, but now we need 300 times the machine to support one user 
badly than we used to run to support 16 users off a Altos 8086 box and 
every user was happy with their "dumb" terminal.

--
Bill
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