iPhone 6 status bar, what is this symbol? See pic What is this symbol? On my iPhone 6, it's on the top by the Bluetooth symbol.phone with keyboard?
That indicates that "iPhone is set to work with a TTY machine."  See the official iPhone manual for additional information (page 13, 165).

http://manuals.info.apple.com/MANUALS/1000/MA1565/en_US/iphone_user_guide.pdf