A/UX® System Administrator's Reference Sections 1M, 7, and 8

serial(7)
2
UIOCDTRFLOW
serial(7)
the signal SIGHUP will be generated to
processes with the port as their controlling
terminal (usually resulting in the
death of the processes and the subsequent
closing of the port). In this
mode, the HSKi input functions as the
RS232 function Data Carrier Detect
(DCD). The following stty(1) command
can be used to put a port into
such a mode:
stty modem < /dev/ttyO
To tum this option off, stty(1) needs
to first open the port; and because it
can't open the port until the HSKi
(DCD) line is asserted, the following
form of the s t t y(1) should be used to
tum off this option:
stty -n /dev/ttyO -modem
DTR flow control. This mode is used
to communicate with printers such as
the Apple Image Writer II. The HSKo
output performs in the same manner as
above. The HSKi input is used to enable
or disable output by a a device
(such as a printer) that wishes to flow
control it When HSKi is asserted
characters may be output, when it is
negated output will stop. Note that
when an A/UX device is closed, the
process that is closing it will be
suspended until all waiting characters
have been transmitted, such a process
will wait until flow control is asserted.
Either of the following stty(1) commands
can be used to tum on DTR flow
control:
stty dtrflow < /dev/ttyO
stty hxctl < /dev/ttyO
February, 1990
RevisionC