Need help identifying sound effect in Alien.
 

So I'm watching Alien and at the 35:11 mark there is an alarm going off on the Nostromo. I have heard this sound effect in some other movie and it's bugging the crap out of me that I can't think of what it is. Any help would be appreciated.

I know this is dumb but it's bugging me.

EDIT TO ADD: I'm referring to the theatrical cut of the film.

Re: Need help identifying sound effect in Alien.
 

I'd love to help but i don't have the movie but around what scene did it happen?

Re: Need help identifying sound effect in Alien.
 

It's the scene where Ash is approaching the air-lock to let Dallas, Lambert and Kane back on the ship.

I tried to find a clip of the scene on YouTube to make things easier but came up with nothing.

Re: Need help identifying sound effect in Alien.
 

I just looked at the scene and I have no idea, sorry.

Re: Need help identifying sound effect in Alien.
 

Thanks for looking. I have given up hope of ever finding out unless it just comes to me someday.

Oh yeah, and it's at the 35:11 mark of the theatrical cut of the movie. I forgot to put that in the original post.

Re: Need help identifying sound effect in Alien.
 

Yeah, I sold my DVDs, and I wanted to hear the effect, so I admit I checked out a few copies of the movie through...other avenues...but they were all the "Director's Cut", which doesn't seem to contain the scene in question at all.

Re: Need help identifying sound effect in Alien.
 

Is it the 3-tone beeps that corresponds with the lights above the airlock door? It sounds familiar to me too, but it's probably one of those sounds that got used in all kinds of sci-fi stuff in the late 70s/early 80s.

Re: Need help identifying sound effect in Alien.
 

After attempting to describe it I've found that it's really difficult to describe a tone. I really wish the flick was on YouTube or something so I could just post a clip. That would makes things so much easier and increase the chances of someone actually knowing it.