ucom/uplcom question

[Marc Skarshinski]

I am having timeout problems on 4.9-Stable using the ucom devices
provided by the "Prolific Technology PL2303 serial adapter (ATEN/IOGEAR
UC232A), rev 1.10/2.02" and also the "Prolific Technology Inc.
USB-Serial Controller, rev 1.10/3.00" driver.  I am trying to read/write
to the port from a couple of shell scripts (one which cats the port, the
other which issues printf statements to the port)

I think this has to do with improper port settings but I cannot get the
settings, issued stty commands, to persist across printfs to the port.
Are there locking devices which can/should be associated with these
devices, analogous to the cuala locking devices for a cuaa device?

Also, the man page for ucom states: "The ucom driver shows a behavior
like a tty", yet were this a standard serial port I would generally use
a cuaa device not a tty.  Is a ucom suitable for controlling a device
which primarily is written (the device is a relay control box)?  Any
help/guesses would be appreciated.  Thanks!

Marc Skarshinski
Atlantis Consulting, LLC