A Look at What’s in Store for Business and Workers : It won’t be dull, that’s for sure. The new year will see dramatic changes for U.S. industry and the American worker. Business writers at The Times polled experts on what is likely to happen in 1989. Here is their report. : TELECOMMUNICATIONS

After five years of decentralization imposed by the breakup of the Bell System owned and operated by American Telephone & Telegraph, technology is beginning to link up the spun-off elements.

Digitization and ISDN (for Integrated Services Digital Network) are the telecommunications industry’s new buzzwords. The technologies are reshaping the old voice-oriented telephone system into an interlocking information gateway that can carry a conversation, computer data and video signals simultaneously over a single pair of copper wires--the ordinary telephone line.

In accommodating these changes, the year will be marked by crucial government decisions altering traditional regulatory methods appropriate to a monopoly environment of the last century but sorely taxed by the new competitive pressures.

The year will be marked, too, by continuing layoffs as telecommunications jobs are eliminated by the new labor-saving technology. And AT&T; will face a major test this spring as its labor contracts come up for renewal.