A quick way to set up the test machine is to unplug the keyboard before turning the machine on. The machine then automatically uses serial port A as the console.
Another way to set up the test machine is to use boot PROM commands to make serial port A the console. On the test machine, at the boot PROM ok prompt, direct console I/O to the serial line. To make the test machine always come up with serial port A as the console, set the environment variables input-device and output-device.
ok setenv input-device ttyaok setenv output-device ttya
The eeprom command can also be used to make serial port A the console. As root user, execute the following commands to make the input-device and output-device parameters point to serial port A.
eeprom input-device=ttya eeprom output-device=ttya
Executing the eeprom commands causes the console to switch to serial port A during reboot.