how do I disable the generation of XOFFs when using tip over a serial port to another device

Wayne Sierke ws at
Sat Sep 6 08:11:39 UTC 2008

On Fri, 2008-09-05 at 12:20 -0700, Jeff Haran wrote:
> Dear Sirs,
> I have connected one of the RS232 ports of my PC with FreeBSD (v6.3) on
> it to a device that does not understand XON/XOFF flow control. I run the
> tip program to connect to that device.
> How do I configure tip and/or the serial port so that the FreeBSD PC
> will NOT send XOFFs or XONs to the device?
> When I run:
> stty -a -f /dev/cuad0
> where /dev/cuad0 is the device associated with the port, it outputs
> (among other things):
> iflags: ... ixon -ixoff ...
> >From my reading of the stty man page, I would think that means the port
> is already configured to not send XOFFs.
> Is there something I need to do to /etc/remote to tell tip to not enable
> Please respond to this email address as I do not subscribe to the
> mailing list.
> Thanks,
> Jeff Haran

Hi Jeff,

I think there might be a problem with the man page for tip(1) on 6.x, as
an entry for 'tandem' was added to the tip sources about 2 years ago.
It's in the 7.x man page as you can see at:

in 'Variables'. 'tandem' shows up in a variable listing (~v) in tip on a
6.x system I have here but I don't have an appropriate set up at hand to
verify that it operates correctly.

Let us know how you go with it. If it works for you then a PR would be
in order.


[1] Extract from the tip(1) man page on 7.x:
     tandem  (bool) Use XON/XOFF flow control to throttle data from the remote
             host; abbreviated ta.  The default value is true unless the nt
             capability has been specified in /etc/remote, in which case the
             default value is false.

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