### RealPort Devices

The RealPort installation creates four different devices for each port in the /dev directory.

- 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.
01-64 | The port number on the individual Digi device.
lowercase letter | At the end of a device name indicates a standard device.
uppercase letter | At the end of a device name indicates a modem device.

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

Device | Path/Name Example
Standard Device | /dev/ttya01
Modem Device | /dev/ttyA01
Standard Transparent Print Device | /dev/pra01
Modem Transparent Print Device | /dev/prA01

#### Standard Device

Example: /dev/ttya01

A standard Digi device uses a lowercase identification letter in their names. 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/ttyA01

Digi modem devices use an uppercase identification letter 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 carrier 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/pra01 and /dev/prA01

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

Use pra01 if the terminal device is ttya01 (standard device); use prA01 if the terminal device is ttyA01 (modem device).