cu

Additional Notes

cu is an older call-up utility for connecting to serial lines, modems, or remote systems. It may appear in UUCP-era documentation and serial console workflows.

Modern users often use screen, minicom, picocom, or socat for serial console access.

Syntax

cu [options] [system]
cu -l device -s speed

Parameters

• system: Named remote system from configuration.
• device: Serial device such as /dev/ttyUSB0.
• speed: Baud rate such as 115200.
• options: Line, speed, and debug controls.

Common Options

• -l DEVICE: Use a specific line or device.
• -s SPEED: Set connection speed.
• -d: Debug mode on some implementations.
• -e: Set escape character on some implementations.

Examples

cu -l /dev/ttyUSB0 -s 115200

Open a serial connection.

screen /dev/ttyUSB0 115200

Common modern alternative.

Practical Notes

• Serial devices often require membership in groups such as dialout or uucp.
• Exit sequences depend on the implementation and escape character.
• Use modern serial tools if cu is not installed or is awkward.