To use the function:

1. You have to connect RS232 cable to the CE624L(local unit). 

2. The mainboard of the PC support the function to wake up the PC via serial connection. 

There will be a setting in the BIOS.  For example, the PC in the link supports "wake up on Alarm".

If PC supports the function, it will use the RI pin to trigger and wake up the PC when you press the pushbutton at remote unit.