As expected, Cingular Wireless is launching a push-to-talk service, using a solution from Kodiak Networks. Though the carrier has yet to make an official announcement, a new page has appeared on its Web site advertising upcoming availability of the service and two new push-capable phones.

Kodiak's solution uses the GSM voice channel to initiate and maintain PTT calls, unlike the push-to-talk over cellular (POC) solutions, which operate over GPRS. That allows Cingular to roll out services across its entire nationwide cellular footprint and take advantage of the inherent quality of service of the voice network, issues that haven't been worked out over GPRS. Cingular and Kodiak also claim that the scale of the solution gives it the broadest PTT coverage in the country, allowing it to match the offers of Verizon Wireless and Sprint.

Sprint currently runs the most successful PTT service in the country over its Nextel network. PTT was built directly into the specification for Nextel's iDEN technology, giving the carrier an early and commanding lead. But other operators have tried to crack the lucrative market using technology built for their networks. While many European carriers have been exploring standards-based POC services pushed by vendors like Sonim, Sprint and Verizon Wireless both chose softswitch-maker Winphoria--since acquired by Motorola--for an IP solution.

While both Verizon and Sprint have had Winphoria's solution running over their networks for several years, there has been relatively little pick-up from customers, at least compared to the strong popularity of the Nextel service. That lack of interest has stemmed mainly from problems with the first-generation of PTT technology. Voice quality has been lower than expected and the lag time between initiating a push call and establishing a PTT session has been as high as 10 seconds due to the inherent radio power intervals of CDMA. Sprint has announced plans to overcome those limitations by moving PTT from its voice network to the IP network in 2008 when it launches EV-DO Revision A networks, which fully support voice over IP.

Kodiak's solution by using the cellular voice channel still faces the same network limitations as other vendors' first-generation solutions, but Kodiak CEO Craig Farrill said that its Real-Time Exchange platform has been engineered from the ground up to meet those issues head on. Kodiak claims to have the fastest speed and lowest latency PTT solution in the industry, and by using the standard voice channel of GSM and CDMA networks, Kodiak can maintain much higher voice quality than POC systems.

"Data channels, don't have quality of service," Farrill said. "Voice channels do."

The deal is Kodiak’s crown jewel as Cingular is the largest carrier to deploy its solution commercially so far. In the U.S., Alltel has deployed Kodiak's real-time exchange, and mobile virtual network operator Amp’d Mobile has announced Kodiak will power its own PTT solution when it launches service next year. In Europe, Orange has launched limited PTT service using Kodiak in France and the U.K.

Cingular will offer the service for $10 a month. Cingular will launch Kodiak’s Real-Time Exchange server as well as a host of enhanced push services, including group push conferencing, instant push voice messaging (or voice SMS), presence and availability features similar to those used in an instant messaging client and the ability to instantly upgrade a PTT session to a full duplex voice call. Cingular has also purchased Kodiak’s gateways, which have the capability to convert POC-based sessions into Kodiak sessions. Though Cingular has announced no plans for an international PTT roaming agreement or inter-carrier operability, it could use the gateway’s capabilities to extend the service to other GSM networks, Farrill said.

Cingular will initially launch the service over two handsets, the LG F7200 and the Samsung D357, both of which will have Kodiak’s embedded clients and dedicated “push” buttons on their keypads. Kodiak has developed a soft client that could be used to upgrade high-end phones for PTT, but Farrill said the solution works better over dedicated devices. “Embedded clients are simply faster,” he said. “There’s no dual-load. There’s only one client operating.”