This is a way of communicating on the half-duplex communication line, includes receiving and transmitting devices (walkie-talkie) by the way of pressing the button for switching to the voice mode or transition to the listening mode. It works as a radio speaker; one can talk by pressing the button and can listen to a voice message by releasing the button.
iVox Communications is a privately funded company, formed in 2004 to build a national VoIP carrier grade network and provide wholesale services to internet and telephone service providers.