Comprehensive Guide to Finding Serial Port Identifiers in macOS Systems

Nov 26, 2025 · Programming · 10 views · 7.8

Keywords: macOS | Serial Communication | Terminal | Arduino | Device Identification

Abstract: This article provides a detailed exploration of multiple methods for identifying serial port device identifiers in macOS systems through Terminal. It focuses on the usage techniques of the ls /dev/tty.* command and offers a complete workflow for testing serial communication using the screen command. The article also covers the ioreg command as a supplementary approach, assisting developers in quickly locating the correct port numbers for serial devices like Arduino and resolving serial communication configuration issues.

Fundamental Principles of Serial Communication in macOS

In the macOS operating system, serial port devices are managed through a Unix-style device file system. All serial devices connected to the system create corresponding device file nodes in the /dev directory. These device files follow specific naming conventions, with serial communication-related devices typically prefixed with tty..

When users connect Arduino development boards or other serial devices, the system automatically detects and creates device files. However, due to differences in device manufacturers, connection methods (such as USB-to-serial adapters), and system configurations, the generated device filenames may vary, necessitating accurate identification of the correct identifier for specific devices.

Using Terminal to Locate Serial Devices

macOS provides powerful command-line tools for system device management. Through the Terminal, users can quickly enumerate all available serial devices. The most direct and effective method involves using the ls command with wildcards to filter serial device files:

ls /dev/tty.*

After executing this command, the system lists all device files starting with tty.. Typical output may include:

/dev/tty.Bluetooth-Incoming-Port
/dev/tty.usbserial-A6004byf
/dev/tty.usbmodem1421

Among these results, identification should be based on device characteristics:

Verifying Serial Communication Functionality

After identifying potential serial devices, the screen command can be used for functional verification. Screen is a terminal multiplexer that also supports serial communication testing:

screen /dev/tty.[yourSerialPortName] [yourBaudRate]

For example, for a detected Arduino device:

screen /dev/tty.usbserial-A6004byf 9600

After executing this command, if the serial connection is normal and the device is transmitting data, the terminal will display the received data stream. To exit the screen session, press Ctrl+A followed by Ctrl+\, then press y to confirm.

Supplementary Identification Methods

In addition to the basic ls command, the ioreg command can be used to obtain more detailed USB device information:

ioreg -p IOUSB -l -b | grep -E "@|PortNum|USB Serial Number"

This command outputs detailed information about all USB devices, including vendor IDs, product IDs, and serial numbers, helping to accurately identify target devices among multiple similar devices.

Practical Application Scenarios

In actual development, especially when using serial proxy tools like Serproxy, correct port identifier configuration is crucial. Incorrect port numbers can prevent normal data transmission. Through the methods introduced in this article, developers can:

  1. Quickly locate newly connected serial devices
  2. Verify device communication status
  3. Configure correct port parameters for development tools
  4. Diagnose serial communication failures

Mastering these skills is significant for embedded development, IoT projects, and any application development involving serial communication.

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