The System Identification (ID) button is available on the front and back of the systems. Press the button to identify a system in a rack by turning on the system ID button. Once you press the identify button it will turn on both identification LED on front and rear of the server.  You can remotely enable identify button using iDRAC or OMSA.  You can also use the system ID button to reset iDRAC by pressing and holding it for 15 seconds
According to the following link: [URL]   What can "i" button do?  I click it once the health indicator will be blinking.  What are other functions?   [IMAGE]      
T440 System health and system ID indicator