Hy there,

I'm monitoring/setting the RS232 status line DCD by the
ioctl (sioControlStatusHandle, TIOCMGET, &sioControlInfo)
and
ioctl (sioControlStatusHandle, TIOCMSET, &sioControlInfo)
commands.

What I don't understand is the question how the Linux-driver recognizes whether I'm programming a modem or a terminal, i.e. whether the DCD-signal acts as an output (setting/writing the TIOCM_CD - bit as a modem) or as an input (getting/reading the TIOCM_CD - bit as a terminal). Actually I'm programming a modem.

The serial device was opened by
sioHandle = open (devString, O_RDWR | O_NONBLOCK | O_NOCTTY);

Thanks for your help!
Regards
Egon