Motorola L3391 Owner's Manual page 82

Internal and Numlock
sets if you can enter a number when Num Lock is turn off. When this
item is enabled, you can press and hold FN, and then press a letter key to
enter a number even if Num Lock is turned off. When this is disabled,
you cannot enter a number with the above method. A check mark (ü)
indicates enabled while undline (_) indicates disabled.
USB Emulation
enables or disables the system's support for the
USB port in DOS mode.
5-6 Setup Configuration Utility