> I would need to look at the code to be sure but
> CTS and CD have special functions for flow control
> and hangup/connect detection that may be altering
> the driver behavior from what you expect.
DCD doesn't have any meaning, unless you set CLOCAL. In this context, DCD
would be used as a logic signal. When its low, the kernel blocks
open()'s/close()'s/write()'s/read()'s. (And if HUPCL is set, a transition
to DCD *LOW* will send kill -HUP to any processes attached to the port.)
CTS doesn't have any meaning, unless you set CRTSCTS.
In this context, CTS would be used as a logic signal. when its low, no
data transmits.
By default, CLOCAL nor CRTSCTS are set.
Therefore...
Chad
>
> Try toggling only RI or DSR and see what happens.
>
> Paul Fulghum [EMAIL PROTECTED]
> Microgate Corporation www.microgate.com
> 9501 Capital of Texas Hwy
> Austin, Texas 78759
> (512)-345-7791
>
> From: Mike Stratoti <[EMAIL PROTECTED]>
> > I am trying to use a serial port not to pump asynch data, but rather as a
> > few digital I/O lines (i.e. I am not using Tx or RX). I want to count the
> > number of times some custom hardware toggles one or more of the modem
> > control lines. These lines will be toggled between 60 to 130 times a
> > second.
> >
> > I don't understand why it takes about 5 seconds to return from the
> ioctl(fd,
> > TIOCMIWAIT...) call. I toggle the modem control lines by hand using a
> RS232
> > breakout box. Although I changed the state of multiple lines multiple
> > times, the numbers displayed are usually incremented by 1 or 2. (Yes, the
> > cables are good and the computer is near 100% idle)
> >
> > I assume the hardware works properly because I can use the same port with
> a
> > standard modem and can sustain a 19,200 baud data stream.
> >
> > What am I doing wrong?
> > Why doesn't the TIOCMIWAIT immediately return the instant that the modem
> > control lines change?
>
>
>
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