Trademark Series Lead the Way to Success : Television: CBS has become the most well-rounded network and is the favorite to win the 1992-93 season.

With the new TV season rolling out in earnest in the next few weeks, CBS--paced by its trademark series “Murphy Brown”--is a heavy favorite to repeat as ratings champ.

If that happens, CBS, which made an unprecedented bolt from last to first place in the 1991-92 season, may settle in for a lengthy period at the top, thanks greatly to its Monday lineup that includes “Murphy Brown” and “Northern Exposure.”

Trademark shows are important on TV. They illustrate to the public what a network wants to be known for at its best. They are standard bearers in defining not only an image but also what kind of audience a network is seeking to earn its profits.

Every network that has had major ratings success can point to trademark shows that have led the way--from “All in the Family” on CBS to “The Cosby Show” on NBC to “Happy Days” on ABC. Each was a significant reflection of the broadcast company that presented it.

Occasionally, other series are also important signature shows: NBC’s “Hill Street Blues” and “Miami Vice,” ABC’s “Moonlighting” and CBS’ awesome soap-opera image with blockbusters “Dallas,” “Falcon Crest” and “Knots Landing.”

Just as CBS’ trademark is “Murphy Brown,” ABC’s counterpart is “Roseanne,” the latest example of how that network traditionally does best in competition when it hits the young adult family audience.

At Fox, the trademark series is, of course, “The Simpsons,” a perfect embodiment of the brash anti-Establishment tone that the young and youth-oriented network has made its own.

NBC, on the other hand, is in desperate need of a signature show to help define itself for the future. The program the network seems to be pointing to is “Seinfeld,” which is witty, intelligent and widely respected--but unfortunately, as a potential ratings power, probably lacks the killer punch of a “Murphy Brown” or “Roseanne.”

The upside for NBC is that its most important trademark series of the 1980s--the show that helped put the network back on the map and earned it respect--was “Hill Street Blues,” which wasn’t a huge ratings hit but attracted a desirable audience that other creative shows could draw on.

NBC is at a crossroads, reeling from the loss of “The Cosby Show” and Johnny Carson, nervous about whether David Letterman will jump ship and dependent on two remaining trademark series--”Cheers” and “L.A. Law”--that are aging and represent the network’s glorious past more than its future.

Curiously, however--despite the ongoing depressing rumors about its fate--NBC actually has a lineup that offers a number of delights. It is, for instance, the principal network bastion of weekly dramas. Four of the five shows recently nominated for an Emmy as best network drama series were on NBC: “I’ll Fly Away,” “Law & Order,” “L.A. Law” and “Quantum Leap.”

In addition, NBC has such ratings winners as “Unsolved Mysteries,” “Empty Nest” and “Wings” as well as other worthy dramas including “Reasonable Doubts” and “Sisters.”

What’s more, Madison Avenue is touting the new romantic sitcom “Mad About You” as a possible winner. And two sets of back-to-back sitcoms could have ratings potential: “A Different World” and the new “Rhythm and Blues” on Thursdays and, on Saturdays, a couple of freshman entries, “Here and Now” with Malcolm-Jamal Warner and “Up All Night” with Patti LaBelle.

But without a true, vital new trademark show to guide it, NBC may be the best-looking loser in years.

What NBC also is lacking is a knockout night such as the “Cosby”-led Thursdays that dominated the 1980s. All the other networks have trademark nights:

CBS’ Mondays, for instance, offer not only “Murphy Brown” and “Northern Exposure” but also “Evening Shade” and two new sitcoms that could well take off as ratings hits partly because they are cushioned among these winners--Diane English’s “Love & War” and Linda Bloodworth-Thomason’s “Hearts Afire.”

English and Bloodworth-Thomason now have a special status on Madison Avenue, right up there with such past and present creators as Norman Lear, Garry Marshall and the team of Marcy Carsey and Tom Werner.

ABC’s powerhouse night, of course, has been Tuesdays, anchored by the ever-improving “Roseanne.”

At Fox, “The Simpsons” does well on Thursdays, but the network’s major night remains Sundays with “Married . . . With Children,” “In Living Color” and “Roc.”

NBC, however, goes into the new season without a predictably reliable trademark evening. Thursdays still have the potential, but NBC must rely strongly on the aging “Cheers” and “L.A. Law” to hold it together. “Wings” has given the lineup new life and the tandem of “A Different World” and “Rhythm and Blues” could help juice the night for the network in a big way if they click.

The new season will help define future ratings battles in another significant area--CBS’ attempt to attract viewers of all ages while ABC, NBC and Fox more and more seem to write off the over-50 audience.

While CBS traditionally has been strong among viewers in their middle and older years, it pulled off a remarkable coup last season that must have galled the other networks: With solid programming and clever scheduling, it not only earned the biggest audience overall, but also was successful in demographic surveys of most age groups.

There’s a clear message in CBS’ philosophy: Most good programs attract viewers young and old. You start with the show and let creative people use their talent. You don’t go about things backward--letting researchers define the creative parameters and then hiring anything-for-a-buck writing and producing mercenaries to grind out shows that numb the senses and further destroy the network system.

CBS thus not only is the favorite to win the season again but also has become the most well-rounded network. It lacks NBC’s lineup of quality dramas but makes up for that in great part with its strong TV movies.

In addition, CBS, because of its solid base of viewers, has been building its news presence even more prominently in prime time. “60 Minutes” is already among the most successful series in TV history. But now, CBS’ “48 Hours” has ranked No. 1 and No. 2, respectively, in the last two weeks of ratings. And “Street Stories” established itself quickly as a newcomer last season.

With its overall momentum, CBS also gets what is reportedly the highest price for a commercial on a weekly network series--”Murphy Brown,” naturally, which pulls an estimated $310,000 for a 30-second spot.

Some trademark.