Minicom

Introduction

The Minicom Router App installs the Minicom terminal communication program — a lightweight tool for serial communication. It provides an interface for connecting to modems, embedded devices, and other equipment via the router's serial ports, with support for:

Configurable serial connection settings (baud rate, parity, flow control).
Session logging to a file.
File transfer using standard protocols (ZMODEM, YMODEM, XMODEM, Kermit).

Installation

To install the Minicom Router App, follow the instructions in the Configuration Manual, section Customization → Router Apps.

To verify the installation, check the Minicom version from the router's CLI:

minicom --version

Starting Minicom

To start Minicom with the last saved configuration:

minicom

To start Minicom and open the configuration menu before connecting:

minicom -s

To connect to a specific serial device directly:

minicom -D /dev/ttyS1

To connect with a specific baud rate:

minicom -D /dev/ttyS1 -b 115200

Minicom opens a terminal window. All Minicom commands are entered using the Ctrl-A prefix key followed by a command key. Press Ctrl-A Z at any time to display the help menu.

Configuration

Serial port settings can be configured interactively via Ctrl-A O (or by launching Minicom with minicom -s). Navigate to Serial port setup to configure the connection parameters.

Serial Port Settings

Setting	Description
Serial device	Path to the serial port, for example `/dev/ttyS1` or `/dev/ttyUSB0`.
Baud rate	Communication speed. Common values: `9600`, `19200`, `38400`, `57600`, `115200`.
Data bits	Number of data bits per character: `7` or `8`.
Parity	Error detection: `N` (None), `E` (Even), or `O` (Odd).
Stop bits	Number of stop bits: `1` or `2`.
Hardware flow control	Enables RTS/CTS flow control.
Software flow control	Enables XON/XOFF flow control.

Serial port configuration items

Select Save setup as default to save the configuration persistently. Settings are stored in /etc/minicom/minirc.dfl.

Key Bindings

All Minicom commands are accessed by pressing Ctrl-A followed by the command key listed below.

Key	Command
`Ctrl-A Z`	Open the help menu (lists all key bindings).
`Ctrl-A O`	Open the configuration menu.
`Ctrl-A X`	Exit Minicom (with modem reset).
`Ctrl-A Q`	Quit Minicom without modem reset.
`Ctrl-A L`	Start or stop session logging to a file.
`Ctrl-A S`	Send a file to the connected device.
`Ctrl-A R`	Receive a file from the connected device.
`Ctrl-A W`	Toggle line wrap.
`Ctrl-A C`	Clear the screen.
`Ctrl-A E`	Toggle local echo.
`Ctrl-A F`	Send a break signal.
`Ctrl-A T`	Open terminal settings.
`Ctrl-A P`	Communication parameters (quick baud rate / parity change).

Minicom key bindings

Session Logging

Minicom can log all terminal output to a file, which is useful for capturing responses from connected devices.

To start logging, press Ctrl-A L. You will be prompted for a file path, for example:

/var/log/minicom_session.log

Press Ctrl-A L again to stop logging. Log files written to /var/log or /opt are persistent across reboots; files written to /tmp are lost on reboot.

File Transfer

Minicom supports several file transfer protocols. The most commonly used is ZMODEM, which supports automatic download triggering and error recovery.

Protocol	Command	Notes
ZMODEM	`Ctrl-A S` → select zmodem	Recommended. Supports automatic start and resume.
YMODEM	`Ctrl-A S` → select ymodem	Batch transfer of multiple files.
XMODEM	`Ctrl-A S` → select xmodem	Basic single-file transfer; no batch support.
Kermit	`Ctrl-A S` → select kermit	Useful when ZMODEM is not available on the remote device.
ASCII	`Ctrl-A S` → select ascii	Plain text transfer without error checking.

To send a file, press Ctrl-A S, select the protocol, and enter the file path when prompted.

To receive a file, press Ctrl-A R, select the protocol, and initiate the transfer from the connected device.

Source Code

The source code for this Router App is available in the public Example Apps Repository.