OT: Translation

I have a German electrical drawing that shows an object with some German text and I am trying to make some sense of it...

Can someone help me with the terms FOTOZ. and FREIG.?

SInce they are abbreviated, I didn't have much luck with babelfish.

Here's a crude excerpt of what I am looking at:




TIA,
Paul

Fotoz: Fotozelle - opto switch
Freig: Freigabe - release

Hope it helps.

Thank you sir!