[Xastir] Xastir and serial port issues

[Jason KG4WSV]

On Dec 4, 2007 7:51 AM, Jim Tolbert <RiverRidge at centurytel.net> wrote:
> I am assuming that Minicom sets the serial port parameters and leaves
> them set.  Does that seem reasonable?

Nope.  Assume that as soon as minicom (or any other app) lets go of
the serial port, the parameters go into a completely unusable state.
That assumption will save you trouble in the long run, even if it
isn't always correct. (:

>  Is there a way to check as to what they are set to?

Technically, yes ("stty </dev/ttyS0" is one), but it isn't terribly
useful as the next application to come along could change the
settings.  The easiest (and as far as I know only) way to ensure
correct operation is for the application that's using the port to set
the correct parameters.

> Should I be running Xastir with Minicom running or not?

absolutely not - only one app at a time can have a serial port.

Note that all these answers are for the _unix_ serial port.  This
tells you absolutely nothing about the device on the _other_ end of
the serial connection.

A quick and dirty test to see if a serial port is functional (or if
you have the correct port) is to bring up a terminal app like minicom,
turn off hardware flow control, short pins 2 and 3 on the DB9
together, and type something - what you type should be echoed back to
the screen by this loopback connection.  There is an actual loopback
device that will test hardware flow control and all that good stuff,
but I have used wire, paperclips, screwdrivers, pocketknife, keys, etc
as field expedient loopback "connectors".

-Jason
kg4wsv