How to: redirecting serial port connections

How to: redirecting serial port connections

Post by Charlie Stro » Sun, 31 Dec 1899 09:00:00

I have a palmtop computer, and an application on it that wants to talk
to a modem. (Note: no TCP/IP, no PPP, no networking. Just a vanilla
modem.) I have a Linux box, and an _internal_ modem, but no external
modems suitable for plugging into the palmtop.

Anyone know if it's possible to redirect i/o on the Linux box's serial
port to the internal modem? The idea is to make the linux box's free
serial port look like a modem to the palmtop. My first idea was something

  cat /dev/ttyS1 > /dev/ttyS2 &
  cat /dev/ttyS2 > /dev/ttyS1

(But obviously this doesn't work or I wouldn't be posting this! -- cat
buffers its i/o, and what we want is raw, not buffered, throughput.)

Any suggestions for how to do it?

-- Charlie


1. Serial Connection Initiating Dial out on Other Serial Port

I am setting up an OS/2 BBS that has the capabilities to connect to the
internet.  I also have a small basic linux system setup.  I am very new to the
linux community and have a lot to learn.  The system is up a running tho'.  My
question is this.  Is there a way for Linux to sense an incoming call on one
serial port and use that to intitiate an outgoing slip connection on the
other serial port.  The incoming connection can be established full time if
necessary then Linux would just have to sense the request for the slip
connection and initiate that call.  The purpose of this is to have dial-up
internet access when a BBS user requests it.  If this can be made to work it
will save me having to have a full-time connection until the demand requires
it.  Any help will be greatly appreciated even to tell me the idea is
ridiculous and can't work. :)  Thanks!  I can also be e-mailed directly at

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