Casio CE-2400O Operator's Instruction Manual page 7

4
Plug the cash register into a wall outlet. Be sure to
check the sticker on the side of the cash register to make
sure that its voltage matches that of the power supply
in your area.
The printer will operate for a few seconds.
5
Insert the mode key marked "OW" into the
Mode Switch.
6
Turn the mode key to the "REG" position.
The display should change to the following.
X
REG
OFF
RF
X Z
REG
OFF
RF
7
Z