NATION

American Telephone & Telegraph Co. named new chairmen at its two largest divisions, AT&T; Communications and AT&T; Information Systems.

Robert E. Allen, 49, currently executive vice president for corporate finance and administration, will head AT&T; Information, the corporation’s marketing and production arm. Randall L. Tobias, 42, will head AT&T; Communications, which handles its domestic and international long-distance telephone business.

The former chairman of AT&T; Information, Charles Marshall, was named an executive vice president at AT&T; corporate headquarters. Morris Tanenbaum, remains a corporate executive vice president with new responsibilities.

Marshall, 55, a former president of Illinois Bell and chairman of the Information Systems division since 1983, will be responsible for corporate personnel policies and external affairs.

Tanenbaum, 56, retains the title he held before he was made a division chairman in the wake of AT&T;’s Jan. 1, 1984, divestiture. His new duties will involve financial management and strategic planning.

“This restructuring signals a further clarification of the role of our corporate headquarters by establishing a more logical integration of its functions,” AT&T; Chairman Charles L. Brown said in a statement.