EXFO FTB-1 - Manual (Page 22)

Safety Information
12 FTB-1
Other Safety Symbols on Your Unit
Other Safety Symbols on Your Unit
One or more of the following symbols may also appear on your unit.
Symbol Meaning
Direct current
Alternating current
Both direct and alternating current
The unit is equipped with an earth (ground) terminal.
The unit is equipped with a protective conductor terminal.
The unit is equipped with a frame or chassis terminal.
On (Power)
Off (Power)