What is Push to Talk feature in mobile phones?

Push to Talk (PTT), also known as press to transmit, is a method by which we can communicate on halfduplex communication lines, including two-way radio, using a momentary button to switch from voice reception mode to transmit mode. A two-way radio can both transmit and receive (a transceiver), unlike a broadcast receiver which only receives content. Two mobile phones having this feature enabled can be used like a walkie-talkie, but, of course, within a limited range.