System icon that looks like ear with line through it on JellyBean I'm Using Sony Xperia P with Android 4.1.2. Can anyone tell what's this icon (one with small T) to the left of battery bar? Is it any application based?
That symbol isn't Android-specific: it's the symbol for a hearing aid induction loop. Some landline telephones have an induction loop that transmits the phone audio directly to the hearing aid, so that hearing aid users can hear the phone call better than they would otherwise. The T stands for "telephone": because the induction loop system originated on landline phones, using the facility requires switching the hearing aid to "telephone mode", usually by flipping a physical switch to a position marked with a T.

It seems your phone has the same facility. The fact the icon is on the right with the "system" icons, instead of on the left with the notifications, shows that it's a part of the OS, not an app. I can't say for sure as I don't have your phone, but I expect you can turn it off in the device's accessibility settings.