Two new TV series skedded for fall have inadvertently set a paradigm for the nets’ upcoming season.

In ABC’s “That Was Then” and the WB’s “Do Over,” the shows’ lead characters travel back to the early 1980s to find out what went wrong with their lives.

Anyone looking at the new fall skeds might wonder if the networks aren’t emulating them.

Coincidence or not, it’s clear that net execs have grown sentimental for simpler times.

That means an age when cable hadn’t stolen their thunder, when even mediocre shows pulled a 30 share and when program choices weren’t subject to issues of corporate ownership.

Hoping to recapture that innocence, next season the nets are playing it safe.

With challenging, out-there fare mostly replaced by a meat-and-potatoes diet of family comedies and procedural dramas, it’s beginning to look a lot more like 1982, rather than 2002, at the webs.

That’s a complete switch from recent years, as the nets looked to stretch conventional boundaries — think “24” and “Alias” — in the hopes of competing with buzz-heavy cablers like HBO.

“Clearly there are many shows that represent a clear moral imperative,” says Universal TV programming prexy Sarah Timberman. “There’s a definite move away from that ‘Sopranos’-esque gray behavior.”

Nets haven’t completely abandoned edgy entries, of course. NBC has even picked up a drama (the drug family saga “Kingpin”) with morally ambiguous “Sopranos”-style characters. And ABC’s reality/drama hybrid “Push, Nevada” promises to alter the form with a quirky “Twin Peaks”-like premise.

But the nets are clearly more wary of rocking the boat.

For example, “Kingpin”–generally considered this year’s riskiest new series — has been limited to a six-episode midseason order.

“The networks are looking for hits anyway they can get them,” says Warner Bros. TV president Peter Roth. “When you have a year where risk-taking shows don’t have success, it causes everyone to be more conservative.”

The nets, still smarting from last year’s marketplace collapse, also hope to lure advertisers back with a much more comfortable environment for their media buys.

And webheads have come to realize that ambitious and daring shows win over critics but don’t guarantee ratings gold these days.

As a matter of fact, critical acclaim has become the kiss of death for many a new show.

Instead, the dramas that pop keep the formula simple and addictive (“Law & Order,” “CSI”), while comedies that have shown life have some sort of family at their core, such as “Malcolm in the Middle” and “My Wife and Kids.”

“If you look over the past couple of years and looked at what the breakout successes were, you had ‘CSI,’ ‘Malcolm in the Middle’ and ‘Bernie Mac,’ ” says 20th Century Fox TV co-prexy Dana Walden.

“It’s hard to miss the point that these close-ended episodic dramas and family comedies are very accessible to mass audiences. There’s no barrier to entry for either one of them.”

Everyone’s gotten into the act, including NBC, which has added self-contained dramas such as “Boomtown” and the adult-skewing family comedy “Hidden Hills” to the mix, in addition to the 1960s-set “American Dreams.”

CBS, meanwhile, has turned Monday night into an entire block of family laffers with the addition of “Still Standing.”

As for drama, four out of CBS’ five new hourlong skeins boast a cop element (“CSI: Miami,” “Without a Trace,” “Hack” and “RHD/LA”), while the fifth is John Wells’ new take on a medical franchise (“Presidio Med”).

Fox keeps it simple with self-contained actioners such as “Fastlane” and “John Doe” in addition to a new generation of Sunday night dysfunctional family sitcoms in the vein of “Malcolm in the Middle” (“The Grubbs,” “Oliver Beene” — which is also set in the ’60s).

WB also stresses family, from “Do Over” and an update of “Family Affair” to the much-ballyhooed new drama “Everwood.”

Then there’s ABC.

The Alphabet web has taken the time machine one step further, hoping to reclaim its glory days of the 1970s and 1980s by returning to a largely mainstream strategy.

For starters, the net plans to promote its 8 p.m.-to-9 p.m. Monday through Friday mix of comedies, newcomer drama “Dinotopia” and “America’s Funniest Home Videos” under the retro-sounding umbrella “The ABC Happy Hour.”

Clearly this isn’t the hipper-than-thou “TV is Good” ABC of a few years ago.

Instead, ABC will be the network of family laffers like “8 Simple Rules for Dating My Teenage Daughter” (starring ’70s network star John Ritter).

Now that the network’s in rebuild mode, ABC Entertainment prexy Susan Lyne says it’s not the time to cultivate critical faves.

“It’s not a question of getting out on a limb,” Lyne says. “We needed to create a new base of shows and then one or two years from now launch maybe some more risky shows. We need the ‘Raymonds’ and the ‘CSIs’ before we go after shows that will be critic darlings.”

Of course, a return to the days of family comedy and accessible drama aren’t next season’s only notable developments. Other trends within this season’s skeds:

  • The nets have finally started to tap into the vast potential of the growing Latino population. Shows like the WB’s laffer “Greetings From Tucson” and ABC’s “George Lopez” put Latinos front and center.

    NBC’s workplace laffer “Good Morning, Miami,” meanwhile, also features a Latina character.

  • Slightly fewer reality skeins — and no gameshows.

    “Never has a network chief been more popular with a network sales department than (Fox Entertainment prexy) Gail (Berman) is with (Fox sales chief) Jon Nesvig,” says Fox TV Entertainment Group chairman Sandy Grushow, presenting a schedule with fewer reality-based skeins.

  • Networks have opted to debut a slew of new shows at 8 p.m., followed by established skeins at 8:30 p.m., in a number of cases — even though conventional wisdom would preach otherwise.

    On Tuesdays, for example, both ABC and NBC will start off the night with new entries (“8 Simple Rules” and “In-Laws,” respectively), saving returning shows “According to Jim” and “Just Shoot Me” for 8:30.

  • The networks have again, for the most part, ordered more of their own inhouse product than ever. All but one of ABC’s fall series come from sister studio Touchstone, for example.

  • Repurposing is out, as nets like the WB and Fox scale back plans to put second runs of shows on sister cable nets.

    Turner topper Jamie Kellner says the advertiser support isn’t yet there to get broadcast-sized CPMs (cost per thousands) on shows such as the WB’s “Charmed.”

    Fox TV Entertainment chairman Sandy Grushow also says the multiplexing of “24” on FX this season didn’t help the cabler.

    “We’ll have to reassess repurposing as a business,” Grushow says.

  • New skeins are a virtual tale of two cities: Miami and San Francisco.

    The Florida hot spot is the setting for shows such as NBC’s “Good Morning, Miami” and CBS’ “CSI: Miami,” while the Bay Area provides the backdrop for Fox’s “Girls Club” and competing hospital dramas “Presidio Med” (CBS) and “Meds” (ABC).

  • The sitcom remains on life support.

ABC, NBC and the WB have skedded only eight laffers apiece next season, CBS just six and UPN four. Fox has the lion’s share at 10.

“This is the heyday of drama,” says NBC Entertainment prexy Jeff Zucker. “Comedy is not king right now, although I’m not saying it’s dead. It’s just that drama is just so in vogue.”

(Josef Adalian contributed to this report).