Nextel launches iDEN service and enjoys several years of strong revenue thanks to the push-to-talk differentiator in the cellular market.

Qualcomm touts QChat technology as an effective P2T competitive solution for CDMA operators. Nextel buys the rights to the technology.

Verizon, Sprint come to market with cellular P2T solutions. Lack of QoS for VoIP services hinder call set-up times and cause latency problems.

Sprint acquires Nextel, cellular P2T solutions improve.

Sprint Nextel iDEN customers begin defecting amid poor network quality claims.

Sprint launches P2T devices based on Qualcomm's Qchat technology in 2008, a move that allowed it to offer push-to-talk services over its EV-DO Rev. A network with the goal of shuttering iDEN network.

Sprint ends QChat amid quality concerns, decides to refocus efforts on P2T over iDEN.

Sprint to launch enhanced version of QChat in the fourth quarter. Major operator poised to launch enhanced VoIP-based P2T from Kodiak Networks with sub-second call set-up.