C H A P T E R  6

TTY Devices

This chapter describes the two different device types supported by the SAI/P device driver, including:

Supported TTY Device Types

The 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:

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.

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 automatically be logged off.