A little known Turkish company may have found a way to turn mobile voice from cheap to plain free. IMS application developer Argela Technologies brought its Multimedia Sponsored Call server to the U.S. at NXTcomm last week, demonstrating an application that plays ads while a caller is waiting for his or her phone call to connect.

Argela vice president of international business development Seyhan Civanlar said that the Sponsored Call server has made the rounds in the Middle East where it was a big success among carriers looking to subsidize voice minutes for their customers or offer voice for free. The application consists of a SIP client on the mobile phone (though it can technically work on a SIP client on a PC, a home phone, even a TV), which is linked to the calling features of the device. Every time a call is made the client links with the Argela server, which then serves up an appropriate video advertisement to the caller, playing in place of the usually ringtone. Once the called party picks up, the video ad stops and the conversation begins.

“This changes the model of voice telephony,” Civanlar said. “Instead of competing against each other in terms of ARPU, operators give that channel to their advertisers.” Advertisers have many types of media they can use to target customers, but it’s becoming more and more difficult to find a captive audience, she said. Putting the ad right on the phone is probably the most captive audience a advertiser can ask for, Civanlar said.

The Argela server can be used to target specific demographics, based upon information collected by the carrier or offered up by the customer when he or she signs up for the subsidized service, Civanlar said. The application can also serve up ads based upon the number called. A call to a rental car agency, for instance, could result in local car rental or hotel ads. Also, because the service is built on an IMS architecture, it’s not necessarily a service that carrier has to offer. An MVNO or a third-party voice provider could offer the service independently of the operator and make payments directly to the service provider, Civanlar said.