US operator AT&T said Thursday that Stan Sigman, president and chief executive officer of its wireless division, will step down after 42 years with the company.

Sigman is understood to have played a key role in bringing the Apple iPhone to AT&T, as well as planning the company’s 3G strategy.

Sigman’s resignation is effective immediately and he is replaced by Ralph de la Vega, group president of Regional Telecom & Entertainment.

John Stankey, AT&T group president of Operations Support, will also add the company’s regional telecom operations to his current responsibilities.