In regards to the length of the noise, I have to add that the noise continues until you end the call!!!! It's weird but there is no conspiracy behind it. Although it did freak me out when I first heard it, I thought someone had tapped my
Phone lol

Probably just static and garbled up interference over the network.

I don't know about this guy he seems like an attention whore. Also he just happened to have a digital voice recorder when this happened?

This obviously isn't aliens, it's a problem that's well known to anyone who works on communications systems. Cell phones operate on an 800 mhz digital trunked radio system, and what you're hearing is the system failing to modulate the signal correctly. It happens on our departments motorola digital radios quite often, operating in the same 800 mhz spectrum.

Yeah it's annoying but it's the nature of the beast. The old VHF analog radios would just bleed static when you were in a low signal area, digital radios just garble it up. Also if the transmission is encrypted it will sound the same way, similar to someone talking underwater. The radios can also "echo" words too. You say a word and it is repeated over and over, each time sounding farther away in distance.

Firefighters hate it because in a large building, some of the low signal areas will cause a radio to completely drop the entire transmission, whereas like i said eariler, VHF simply adds a momentary burst of static.

One, someone that knows what causes this, PLEASE log into YT and explain it to this man. Nicely, but let him know. He's clearly shaken up over the whole thing. Two, i agree that the noise sounds like electronic errors, somehow broadcasting through the phone. Apparently the guy doesn't check into such things. That said, his heart is in the right place. He feels it's a sign of something, and wants to warn people. So if you respond there, be kind?

Now, what I really want to know is, where did he GET all those cool colored shades? All I ever see is red and blue. Love the colors!

Oh, as a side note....does anyone in the thread think there has ever been any legit interception of such communications? Never really heard of such a thing, save in the one movie......so is it something that happens, or did M Night make it up?

Some people will go to ridiculous lengths to get attention.
The sound is made up and was almost certainly played on some sort of synthesizer or even some free software on a laptop or PC.No amount of filtering (sine wave or otherwise) will get anything coherent from something that is completely random.
The sound quality is too good to have been taken from a speaker of the size found in a mobile phone,I've heard people who have done this and they are nowhere near as clear as that.
As mentioned above,all cell phone communications are digitally encoded and there is no way they can be affected by atmospherics that are audible in the same way as say an analogue car radio or TV receiver can.A loss of or weak signal will chop the sound up,but won't and can't re-assemble it into another completely different coherent sound
For the claimed aliens to be able to tap into a cell phone network,they'd have to work out the exact protocols and algorithms that let the different handsets and cell sites talk to each other.If they have the knowledge and technology to do this,don't you think they'd do just a little bit more homework and broadcast the message in the native language of those they're trying to make contact with,instead of needing to get the Clangers to translate it?

I'm sure this guy has lots of loyal followers who all take every word he says as gospel,but isn't it strange how aliens only ever use religious charlatans to make contact with us?