Restoring non-functional terminals

A completely non-functional terminal displays no login prompt and does not respond to keyboard input. This situation is usually caused by hardware failure or configuration problems. To check a non-functioning terminal:

1. Check the brightness control on the terminal.

2. Check the power and communication connections at the terminal and computer.

3. If applicable, enter set-up mode on the terminal and verify the terminal configuration settings. The settings should include 9600bps, 8 data bits, 1 stop bit, and no parity.

4. Enable the port to which the terminal is connected. For example, to enable tty2a, use the following command:
   
   enable tty2a

5. Verify that there is a getty process associated with the terminal port. For example, enter:
   
   ps -t tty2a

6. Test the hardware communications by disabling the port and redirecting output to the non-functional terminal: for example, to test tty2a, use the following commands:
   
   disable /dev/tty2a
   echo hello > /dev/tty2a