Can a big computer manufacturer dealing with thousands of small vendors and customers avoid trampling on at least some of them? Probably not, but Control Data Corp., a $3.1-billion giant, is trying to make it easier for its small company clients to at least say "ouch."

Recently, the Minneapolis-based computer maker installed a toll-free hotline for its customers and suppliers. Now, 24 hours a day, callers can beef about such things as late payments and shoddy service -- or just vent their frustrations over business glitches.

The hotline is staffed by Control Data employees who, according to James R. Morris, vice-president of the corporation's Control Data Business Advisors Inc. subsidiary, have been trained to recognize the key complaint even in a flurry of abusive language. Frequently, Morris says, late bill-paying cases can be settled easily, since many are the result of something as simple as a lost invoice number or an employee on vacation. In any event, he says, all callers get a report, within 24 hours, on what's being done.

Whether the hotline will be anything more than good public relations remains to be seen. However, that in itself may be valuable. "Lots of small suppliers don't want to do business with Sears Roebuck, Ford, or the federal government," says a Small Business Administration official. "A hotline could be good advertising if you want good suppliers."

In fact, Control Data, which has been selling business expertise to small companies over the past decade, will sell the complaint hotline idea and format to others, beginning next year. Morris believes the most likely candidates will be large companies whose suppliers and customers include a high proportion of small firms.