Epson Endeavor L User Manual page 51

Some copy-protected programs require the computer to run at
slow speed while accessing the program on a diskette. These
programs also usually require you to leave a key disk-the
diskette that contains the copy protection-in the diskette
drive. If you use a copy-protected program, you can change the
speed to slow to access the diskette and return it to fast speed
when you are finished.
You can change the processor speed temporarily by entering
one of the following commands from the numeric keypad on
your keyboard :
0 To select slow speed, press Ctrl Alt -,
To select fast speed, press Ctrl Alt +.
0
(Hold down the Ctrl key and the Alt key simultaneously and
then press the -or + key on the numeric keypad.)
Note
You can use the commands listed above while you are
running a program. However, if the program uses one of
these commands for another function, you cannot use it to
change the processor speed. You can, however, enter the
command at the MS-DOS command prompt or change it
through the SETUP program.
The speed setting remains in effect until you turn off or reset
the computer, change the speed with a keyboard command, or
change the speed using SETUP.
Using Your Computer 3-9