Command Word
If no activation method is suggested either in the item description or by the nature of the item, assume that a command word is needed to activate it. Command word activation means that a character speaks the word and the item activates. No other special knowledge is needed.
The Knowledge (arcane lore) skill might be useful in identifying secret command words or deciphering clues regarding them. A successful check (DC 30) is needed to come up with the word itself. If that check is failed, succeeding at a second check (DC 25) might provide some insight or clue to discovering the command word or phrase.
Activating a command word FX item is an attack action and does not provoke attacks of opportunity.