Duluth-based NCR Corp. has reached a deal to sell 40 self-service check-in kiosks to China Southern Airlines, one of China's largest passenger airlines.

Earlier this year, China Southern bought 30 of the kiosks, which allow passengers to check in, scan or print boarding passes, find flight information and request mileage credit.

The terms of the deals were not disclosed, and a company spokeswoman said the price of the kiosks depends on each customer's "unique operational and environmental requirements."

The first 30 kiosks are operating in China Southern's hubs in the large cities of Guangzhou, Shenzhen, Changchun and Zhengzhou. Those from the most recent order will be installed in Beijing, Shenzhen, Urumqi and Dalian, according to an NCR news release.

About 30 percent of China Southern passengers in Guangzhou are opting to use the kiosks, and the airline expects that number to grow, according to the release.

At Hartsfield-Jackson Atlanta International Airport, the world's busiest by passenger volume, self-service check-in has grown by 215 percent in the past four years, according to data released on Oct. 13 by the Airports Council International-North America. Overall, 46 percent of passengers at Hartsfield use kiosks to check in, up from 32 percent four years ago.

About 8,400 NCR kiosks are used at more than 300 airports around the world.

Delta Air Lines Inc., one of NCR's largest airline customers, has 133 at Hartsfield.

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