The RealPort installation creates two different Unix devices in /dev for each port: a standard device and a transparent print device. DG/UX uses long names and short names for each device. The short names for RealPort devices have a DG/UX standard form and an optional alternate form.
DG/UX standard serial port devices have short names in the form
ttyNN
where NN is a number. The built-in serial ports are normally tty00 and tty01; then the RealPort serial ports begin with tty02 and continue counting up. However, the exact numbering depends on what other standard serial ports devices are configured in the kernel. Transparent print devices do not have short names in this form. DG/UX system administration utilities, like sysadm, require names in this form.
In addition, if you specified server_port_names on in the /etc/realport.conf file, RealPort standard serial ports have short names in the form
tty-SERVER-PORT
and transparent print devices have short names in the form
tty-SERVER-PORTp
where SERVER is the number identifying the server (from the /etc/realport.conf file) and PORT is the port number on the PortServer, counting from 0. These names cannot be used in sysadm when setting up terminals, modems, or UUCP devices; however they can be used in sysadm when setting up a printer and in most other contexts outside sysadm where a Unix character device name is expected.
For example, assuming your DG/UX system has only the two standard built in serial ports in addition to RealPort devices, the first port on the first PortServer would be named /dev/tty02 or /dev/tty-0-0, and the corresponding transparent print device would be /dev/tty-0-0p. If you had two PortServers, the first with one expansion module for a total of 32 ports, the first port on the second PortServer would be named /dev/tty34 or /dev/tty-1-0.
Each device also has a long name, which is rarely used directly. See the release notes for a description of these names.
Examples: /dev/tty02 or /dev/tty-0-0
The default handshake method is XON/XOFF. Data Carrier Detect must be present to open the device. To allow the device to be used without the Data Carrier Detect signal, use
stty-ncxa forcedcd /dev/ttyNN
To configure a RealPort to be used as a login port, use sysadm and choose Device, Port, Terminal, and then Add. To ensure that a login session will be terminated when carrier is dropped, select a modem TTY definition label for the newly added login port, like M9600; if a direct connection TTY definition label like 9600 is used, the login session will not be terminated when carrier drops. Complete details on setting up login ports can be found in Setting Up and Managing Terminals on the DG/UX System on the DG/UX user documentation CD that came with your system. See also Configuring a Device for a Terminal.
When used with a terminal or other device, it is usually wise to use a modem TTY definition label and to wire the Digi DCD signal to the terminal's DTR (Data Terminal Ready) line. When the terminal is turned off, any associated jobs are killed, and the user is logged out.
Example: /dev/tty-0-0p
The "Transparent Print Devices" (DigiPRINT) can be used with
auxiliary printer ports on terminals. Output directed to a
transparent print device goes out the auxiliary port of a terminal
while the user continues to use the terminal normally.