'Bill Cosby Show' - earmarks of an endearing hit

Bill Cosby is back on prime-time series TV with a group of his favorite kind of people - children. ''Wholesome'' is the word for The Bill Cosby Show (NBC, Thursdays, starting Sept. 20, 8-8:30). But wholesome with a glint in its eye.

Just about everything Bill Cosby does seems to be permeated with taste, judgment, wit - and just a bit of mischief. ''The Bill Cosby Show'' is no exception. It's intelligent, responsible, droll fun, studded with charming little shocks of recognition for the whole family.

But don't expect Red Foxx- or Eddie Murphy-style ethnic humor. This new series is not about a black middle-class family; it concerns itself with a middle class family of ''yuppies'' who happen to be black. If the mild, laid-back humor is indigenous at all, it is indigenous to families. This very universality may subject the show to some criticism from black groups - the same kind of activists who criticized ''Julia'' many years ago for being ''too white.''

In the premiere episode, most of the time is used to introduce the main characters - obstetrician Cosby, his lawyer wife, and their four children, who live in an apartment above his offices in a New York City brownstone. Nothing much happens - the oldest daughter insists on dating a boy who wears an earring in one ear; one son finds it difficult to distinguish between being ''a real person'' and a lazy student. The dialogue on cost-of-living for a young person today is typical Cosby-esque - amusing, discerning, and at the same time very relevant.

Perhaps it suffers a bit by comparison with those utterly charming 30-second Coca-Cola commercials, which Cosby has been doing for the past few years - it's difficult to sustain warmth and charm for a full 30 minutes. But with Ed Weinberger (one of the old ''Mary Tyler Moore Show'' people involved with Cosby himself in producing and writing), ''The Bill Cosby Show'' - despite its lack of superficial flash - has all the characteristics of an electronic perennial. I predict that the buds revealed in this promising premiere will surely burst into full bloom in the weeks - probably years - to come.