Legrand data key for the AlphaRex³ series. The data key can be used to read switching programs into the clock. The 'READ KEY' function must be selected on the clock. The data key can be easily programmed using a PC. The 'WRITE KEY' clock function can be used to transfer programs from the clock to the key, so programs entered on one clock can be easily and quickly transferred to other clocks and/or backup copies can be created.