AT&T's board of directors has named David W. Dorman, current president, as chairman and chief executive to replace C. Michael Armstrong when he departs the company.

Armstrong, 64, is scheduled to become the new chief executive of AT&T Comcast when regulators approve the merger of AT&T Broadband and the Philadelphia cable company.

The announcement that the 48-year-old Dorman would replace Armstrong makes the appointment official. The expectation had been confirmed and reported in past news stories.

Dorman is expected to succeed Armstrong when AT&T completes the spin-off of the broadband unit and merges it with Comcast. Shareholders of both companies recently approved the spin-off but two major regulatory hurdles remain before the deal could be expected to close by the end of the year.

Before joining AT&T as president in December 2000, Dorman worked in a number of capacities as part of the phone giant's AT&T Labs research division. Since February of this year, he's been a member of the company's board of directors.

Prior to AT&T, he worked for Internet news service PointCast, and telecommunications companies Sprint and Pacific Bell.