What are indicator L.E.D. 's on the left of the phone used for?

[chicostyles]

i see two indicator lights on the opposite side of the regular notification L.E.D. 's but they never turn on im wondering what are they for? thanks for any responses This site ROCKS!!!!:icon_ banana:

 

[stanrc]

The top left is the proximity sensor, so the screen turns off when you hold it up to your face when you are talking. The top right has the light sensor and the notification LED.

 

[chicostyles]

i see, thankz for the quick response