What is this iPhone icon?

[mightyjlr]

I have had 3.0 installed for a few days, and last night an icon showed up in the upper right corner that I haven't seen before. What is it? Never saw it on 2.0.

 

[DeltaMac]

That status icon tells you that your iPhone is set for use with a TTY machine.
Here's page that explains those various status icons: http://www.apple.com/iphone/how-to/#basics.status-icons

 

[alra111]

Yeah, looks like you accidentally turned that on in the settings...