TonidoPlug2 has three LED indicator lights on the side:
The wireless and HDD indicators indicate wireless and hard disk activities respectively.
The status indicator indicates various status of the plug:
Blinking blue: The plug is initializing and starting up.
TonidoPlug2 has a three position switch on the side.
TonidoPlug (version 1) has two LED lights:
The top light indicates power and is normally orange when plug receives power
The bottom light indicates various status of the plug: