Push-to-talk app Zello has revealed a data breach that exposed users' email addresses and hashed passwords after discovering unauthorized activity on their systems. (Read more)
Push-to-talk or press-to-transmit is a method of conversation over a half-duplex link, based on pressing a button to switch from reception mode to transmission mode.Wikipedia
Zello is an app startup located in Austin, Texas, originally building Zello apps. The apps emulate push-to-talk walkie-talkies over mobile phone networks. Wikipedia