Disaster volunteer Zello Channel

Zello acts as a replacement for traditional two-way radios, offering additional features such as history, replay last message, notifications and Bluetooth device support. It works over 2G, 4G, 3G and GPRS/EDGE networks. Zello is "a direct messaging service that allows members to communicate freely either privately with individuals or over open channels that can support hundreds of thousands of users," said U.S. Senator Ted Cruz.  It allows people to use cell phones and computers all around the world like walkie-talkies.

Zello users can create channels and give control to other Zello users to become moderators. New York Times' technology columnist David Pogue describes Zello's channels, "Like most of the best applications, Zello lets you create groups so that you can carry on something like a party-line phone call among a handful—or hundreds—of friends or collaborators.