Serial port operation -

Maciek Borzecki maciek.borzecki at
Tue Nov 29 22:58:20 UTC 2011

At Tue, 29 Nov 2011 17:48:45 -0500,
Bob Goodwin wrote:
> On 29/11/11 16:14, Tim wrote:
> > On Tue, 2011-11-29 at 14:14 -0500, Bob Goodwin wrote:
> >> I have two F-15 computers with a program that should be toggling
> >>          RTS and DTR on the serial port. One works as expected this one I
> >>          am on now does not.
> >>
> >>          I haven't had much to do with the serial port and don't know how
> >>          to troubleshoot it.
> >>
> >>          Can someone offer a suggestion where to begin?
> > Obvious first line of thought:  Are you using two different serial
> > cables?  And, if so, is the non-working one fully wired?
> >
>         I eliminated that possibility and swapped the cables, one worked
>         "out of the box" this one doesn't. I was hoping it would be some
>         configuration problem but don't know where to look. One is
>         F16-32bit, this one 64 bit, however they are different
>         computers, this one an HP, the other Dell, both of roughly the
>         same vintage.

Disable flow control and connect through a null modem cable to another
PC. Fire up minicom, set both to 8N1, same speed for both and you
should be able to see characters pop up on the other end while typing.

Maciek Borzecki

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