.Nd "control the bidirectional status of a sio port and waiting time after DTR drop"
is used to examine and modify the bidirectional status
and its waiting time after DTR drop.
will print the current port state
(if kernel was built with
to indicate that bidirectional operation is enabled or
to indicate that it is disabled, string
and current waiting time in ticks
To modify the status of the port or waiting time, simply
specify the desired new state
on the command line. All users with
to get the port's status and current waiting time.
Only root can set a port's status and waiting time.
By default, each port is initially unidirectional, waiting time is
is to put invocations of it in the
.Cm TIOCMSBIDIR: Inappropriate ioctl for device.
This indicates attempt to change port status on
a non-sio special device file,
or the kernel has not been built with
For more information concerning reconfiguration
.Ar /usr/src/sys/i386/doc/config_options.doc.
It is strongly recommended that you do *not*
change the bidirectional status of a port while there are programs
using the port. Read that as: if you do, and it breaks, don't yell
at me; that's a really weird thing to do.
Originally part of cgd's com package patches, version 0.2.1, to 386BSD 0.1.