iPhone AT&T In-call notification noise

[Dekema2]

Just a general question about some phone calls, I was on a call with my dad and in the background I heard a noise that sounded like a piece of metal going down an xylophone, but it sounded like some kind of connection notice or something of that nature. I've heard it before, does anyone have an idea on what it could be?

 

[jim.hickman.777]

It means you have a defective phone. Put it in a red hazmat bag and take to where you bought it it has Ebola!

 

[Mr Hands]

That just means the government was tapping in to your connection to make sure nothing bad was going on.

They listen in for our safety and security. I wouldn't worry about it too much. Unless of course you actually have something to hide...

 

[Dekema2]

Lol these are some silly replies!

Really though I wonder who else may have heard this

 

[Dekema2]

Okay, so I was in a call with people and I heard the noise again, and when Low Batter: 10% remaining came up, I heard it again, this time much clearer. Any thoughts?

EDIT: Look what I found on Stackoverflow!!!

I have had the following iPhone models:

iPhone
iPhone 3G
iPhone 3GS
iPhone 4
iPhone 4S
All of this time I was using AT&T. None of the phones were jailbroken. My current model is iPhone 4S on AT&T.

I noticed this recently during a call. I had never noticed it before, and I'm a heavy user. I'm not sure if it was something adding during an update by the carrier (AT&T) or one of the iOS updates.

A person on another forum mentioned noticing it ever since the iPhone 3GS. Based on my research so far, it appears that it's inconsistent.

http://apple.stackexchange.com/questions/77000/does-iphone-5-have-a-low-battery-warning-tone

I'm on ATT with a 5s. If anybody wants to test this theory, be my guest.