Telecom-industry leaders Nokia Corp. and Alcatel-Lucent know the importance of quality work and long-term relationships. So it is no surprise that both have been regular customers of well-known electronic manufacturing services (EMS) provider Kyrel Oy for more than a decade.

HARRISBURG, PA—Foxconn Technology Group, the Taipei-based maker of Apple Inc.’s iPhone, plans to invest $40 million to build a high-tech assembly plant here.