Mysterious iPhone Status Bar Icons

So I picked up my wife’s iPhone 3G and immediately noticed an weird status icon of a telephone and keyboard above the status bar on the iphone. It looked like it was saying that a phone was raining.

I had never seen this icon before so I figured I’d go through the menu’s to figure out what activated it. Couldn’t figure it out, so I then decided I’d do a search but wasn’t really sure how to describe it.

Eventually…

Shows that TTY is on:

Teletype (TTY) machines are used by deaf and hard of hearing people to communicate by typing and reading text. If you have the iPhone TTY Adapter cable, available at www.apple.com/store, you can use iPhone with a TTY machine. Choose Settings > Phone to turn TTY on or off.

http://support.apple.com/kb/HT1558