### RealPort Devices

The RealPort installation creates four different devices for each port.

- Standard device
- Modem device
- Standard transparent print device
- Modem transparent print device.

#### Device Name Format

The devices are named according to the following conventions:

a-z | The Digi device letter ID. Legal letters are a-z.
001-096 | The port number on the individual Digi device.
s | At the end of a device name indicates a standard device.
m | At the end of a device name indicates a modem device.

Here are examples of the devices created for the first port of a Digi device with the identification letter "a".

Device | Path/Name Example
Actual Standard Device (terminal) | /dev/dty/a001s
Actual Modem Device | /dev/dty/a001m
Standard Device Link (terminal) | /dev/cua/a001 (linked to /dev/dty/a001s)
Modem Device Link | /dev/term/a001 (linked to /dev/dty/a001m)
Standard Transparent Print Device | /dev/dpr/a001s
Modem Transparent Print Device | /dev/dpr/a001m

####
Standard Device

Example: /dev/dty/a001s

A standard Digi device uses an identification letter "s" in its name. The default handshake method is XON/XOFF. Data Carrier Detect (DCD) 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 active processes on the port to be killed and the user will be automatically logged off.

#### Modem Device

Example: /dev/dty/a001m

Digi device modem devices use an identification letter "m" in their names. They are sometimes referred to as "dial-in" devices.

Modem devices are traditional UNIX ports with modem control. They require Data Carrier Detect to be high before they will operate. RTS/CTS handshaking is enabled by default. When used with a modem, the ports will wait for DCD before sending out the login prompt.

When used with a terminal or other device, it is usually wise to wire the Digi DCD signal to the terminal's Data Terminal Ready (DTR) 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.

#### Transparent Print Devices

Examples: /dev/dpr/a001s and /dev/dpr/a001m

The transparent print devices can be used with auxiliary printer ports on terminals. Output directed to a dpr device goes out the auxiliary port of a terminal while you continue to use the terminal normally.

Use /dev/dpr/a001s if the terminal device is /dev/dty/a001s or /dev/cua/a001 (standard device); use /dev/dpr/a001m if the terminal device is /dev/dty/a001m or /dev/term/a001 (modem device).