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C H A P T E R
6
TTY Devices
This device driver supports two different device types on each line. On line “
a000
”,
where “
a
” refers to the first SunSAI/P board, and “
000
” refers to first line (port) on
that board, there are two devices:
/dev/term/a000
Dial-in TTY device, used for terminals, modems, printers, laboratory equipment,
etc.
This device is a traditional UNIX port with modem control. It requires Data
Carrier Detect (DCD) to be high before it will operate.
When used with a modem, the port will wait for carrier before sending out the
login:
prompt, so the user is greeted properly upon making a connection.
When used with a terminal or other device, it is usually wise to wire the
SunSAI/P DCD signal to the terminal's DTR (Data Terminal Ready) line. When
the terminal is turned on, the system outputs a
login:
prompt. When the
terminal is turned off, any associated jobs are killed, and the user is logged out.
/dev/cua/a000
Dial-out TTY device. This is the same as
/dev/term/a000
with the exception
that Data Carrier Detect need not be present to open the device. Once a
connection is established and DCD becomes active, standard devices behave in
the same way as modem devices-subsequent loss of the Data Carrier Detect signal
will cause the jobs to be killed and the user will be automatically logged off.