Configuring Serial Communication

Serial communication is often required when interfacing lab machines with a computer. This guide explains how to properly configure and troubleshoot serial connections on both Windows and Ubuntu.

🪟 Windows Setup

1. Identify Your Cable Type

• Direct serial (DB9 to DB9): No drivers typically required.
• USB to Serial: Requires a driver based on the cable chipset (Prolific, FTDI, CH340, etc.).

2. Install the Correct Drivers

🧰 Option A: Automatic via Windows Update

• Plug in the USB-to-Serial cable.
• Windows may automatically find and install a compatible driver.

🧰 Option B: Manual Installation

If Windows doesn't install the correct driver:

• Prolific-based cables:

  • Download the official Prolific driver
  • Avoid older or cloned cables, which often cause issues with newer drivers.

• FTDI-based cables:

  • Download FTDI VCP drivers

• CH340 cables (common with low-cost devices):

  • Download CH340 drivers for Windows

💡 After installation, check Device Manager under “Ports (COM & LPT)” to confirm the COM port number.

🐧 Ubuntu Setup

Ubuntu supports most serial-to-USB adapters out of the box — no driver installation required.

1. Grant Access to Serial Ports

Add your user to the dialout group with:

sudo usermod -a -G dialout $USER

Then log out and log back in or reboot for the change to take effect.

2. Verify the Serial Device

Check the connection with:

ls /dev/ttyUSB*

or

dmesg | grep tty

💡 Typical device names: /dev/ttyUSB0 or /dev/ttyS0

🧪 Testing the Connection (Windows)

Use Hercules SETUP Utility — a free and reliable tool for testing serial and network communication on Windows.

🔧 Steps:

1. Download Hercules
2. Launch the app — no installation required.
3. Go to the Serial tab.
4. Select your COM port and set baud rate (e.g., 9600).
5. Click Open to start the connection.
6. Use the input box to send commands and view responses in the log window.

💡 Make sure the serial device is connected before launching Hercules.

📷 Screenshot:

Image Source: HW Group

🎥 Live Demo:

Watch a Hercules Demo on YouTube

✅ Tips & Troubleshooting

• Always match baud rate, stop bits, data bits, and parity to your device settings.
• Restart apps after switching ports or replugging the cable.
• Avoid using hubs or extenders when troubleshooting — plug the cable directly into the computer.
• If you're unsure of your cable’s chipset, use Windows Device Manager to check under Ports (COM & LPT).