Spells (3e)

Alarm sounds a mental or audible alarm each time a creature of Tiny or larger size enters the warded area or touches it. A creature who speaks the password (determined by the character at the time of casting) does not set off the alarm. The character decides at the time of casting whether the alarm will be mental or audible.

Mental Alarm: A mental alarm alerts the character (and only the character) so long as the character remains within a mile of the warded area. The character notes a single mental "ping" that awakens the character from normal sleep but does not otherwise disturb concentration. A silence spell has no effect on a mental alarm.

Audible Alarm: An audible alarm produces the sound of a hand bell, and anyone within 60 feet of the warded area can hear it clearly. Reduce the distance by 10 feet for each interposing closed door and by 20 feet for each substantial interposing wall. In quiet conditions, the ringing can be heard faintly up to 180 feet away. The ringing lasts for 1 round. Creatures within a silence spell cannot hear the ringing.

Ethereal or astral creatures do not trigger the alarm unless the intruder becomes material while in the warded area.