The input-device and output-device variables control the firmware's selection of input and output devices after a power-on reset. These are the default values:
input-device – virtual-console
output-device – virtual-console
The values of must be device specifiers.
When the virtual machine is reset, the named device becomes the initial firmware console input or output device. (If you want to temporarily change the input or output device, use the input or output commands.
{0} ok setenv input-device device-specifier
{0} ok setenv output-device device-specifier