NEW YORK — AT&T Inc. said Friday that the shutdown of its second-generation, or ‘‘2G,’’ wireless network will be complete by the end of 2016, a process that will force customers with older phones to upgrade to ‘‘3G’’ or ‘‘4G’’ handsets.
In a regulatory filing, the Dallas company said 12 percent of its customers on contract-based plans, or 8.4 million people, have 2G phones.
AT&T said it is shutting down the older network, which does not support high data speeds, city by city. It said earlier this year that the process has started in New York City, and it’s trying to move the city’s 2G subscribers to new phones.
By shutting down 2G and using the same space on the airwaves for 4G, AT&T can increase data capacity by more than a hundredfold. Data use is skyrocketing as people adopt smartphones, and the company is facing a ‘‘spectrum crunch’’ in some areas.
Among the 2G devices on AT&T’s network are the first Apple iPhone, which debuted in 2007.
Other companies are also ‘‘refarming’’ 2G spectrum. Sprint Nextel is shutting down the Nextel 2G network and moving subscribers to Sprint 3G.
The second generation of wireless technology debuted in the 1990s and was the first one to apply digital technology to cellphones, boosting call quality and network capacity. Third-generation networks, with higher data speeds, started becoming widespread in the United States about six years ago.