Push-to-Talk IPRS (IP Radio Service) always-on instantaneous communication technology enables one-to-one and one-to-many, two-way voice and data sessions that do not require dial-up - subscribers push a button and begin speaking.

The Kodiak Real-Time Exchange System: Instant Wireless Voice
By Kodiak Networks, March 2004

Ericsson Instant Talk: A Revenue-Generating IP Multimedia "Killer" Application
By Johan Bjorklund, Manager, Technical Marketing Ericsson CDMA System, April 2003

Q-Chat: The Complete Push-to-talk Solution for CDMA Operators
By Internet Services Group, Qualcomm, 2003