Testing the serial ports
You will need:
  • The machine to be tested
  • Screen
  • Keyboard
  • Crossover or "null modem" serial cable
  • Connection to the internet

Step 1 - Connect the peripherals

Connect the screen, keyboard and serial cable, then power the machine up. Log on to the desktop.

Step 2 - Prepare the test

First, make sure that the screen program is installed. Open a Terminal window and run the following commands.
1
sudo apt update
2
sudo apt install -y screen
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Now open a second Terminal window.

Step 3 - Run the test

Run one of the following commands in each of the terminal windows:
1
sudo screen /dev/ttyUSB0 19200
2
sudo screen /dev/ttyUSB1 19200
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After running each command, the console will go blank with just a blinking cursor. Now run the following tests
  • Click on the first terminal and type some text. It should appear in terminal 2
  • Click on the second terminal and type some text. It should appear in terminal 1
If either of these tests fail, please double check the isolated port has been correctly installed.
Assuming both tests pass, simply close the terminal windows.
Last modified 4mo ago