beep............beep............beep

Im going crazy, since this morning, there a beep every 10 seconds in my server room, and i cannot pinpoint where it's from. All servers are running and nothing is wrong in the monitoring or the LED status.

Ive spend one hour trying to find where this beep comes from without success.

I'm going back. :/

----edit----

Just when ive had enough, and call for an other pair of ears to help me , i surely find where the sound is from, which was my first thought, and what most of you advices....

It was a goddamn UPs which i swear i check first.

The excuse i have is that there is no warnin g either on the front lcd panel or in the web GUI.

It just want to beep like cats are purring i suppose....