New York ? Bars and restaurants that try to entice customers by showing Paulie Walnuts, Ralphie Cifaretto and the rest of “The Sopranos” gang on Sunday nights are hearing from another type of enforcer.

HBO lawyers are sending out letters telling them to turn the sets off, since it’s illegal to show the network’s signal in public places.

“I got whacked!” said Frankie Janisch, owner of “Frankie J’s” restaurant in Chicago, who received a cease-and-desist letter from HBO four days after the Chicago Tribune wrote about his Sunday night promotion surrounding the hit mob drama.

He’s no longer showing episodes of “The Sopranos” on his restaurant’s televisions.

As a pay cable service, HBO is only supposed to be shown in private homes and hotels, said Jeff Cusson, a spokesman for the network.

“If you’re paying $10 a month to get it into your residence and can go into a public establishment and watch it, it’s obviously not as appealing,” he said.

HBO has always been on the lookout for people who use their signals, particularly to show high-profile boxing matches. But with “The Sopranos” and “Sex and the City” big favorites, they’ve become the subject of promotions, too. The season-opening episode of “The Sopranos” in September drew the largest audience in the network’s 30-year history.

Open your doors, put some extra Italian food on the menu and presto! a normally slow Sunday night has some buzz.

That was Janisch’s idea. He hired actors for a brief floor show one taped napkins to the side of his head to approximate Paulie Walnuts’ distinctive gray streak named menu items after show characters and aired fresh episodes each week.

“I was trying to have some fun with it,” Janisch said. “At the same time, I’m trying to make a living in a tough economy.”

He believes he’s more likely to get new fans, potential HBO subscribers, interested in the show than attract people who are trying to circumvent the network’s monthly fee.

While there’s no actual law against showing HBO’s signal publicly, Cusson said people who get HBO through their cable or satellite provider agree to follow those rules.

HBO would be in violation of its own agreements with movie companies if the network knew its signal was being seen in public and wasn’t doing anything about it, he said.

Establishments that persist showing HBO programs despite the cease-and-desist letter could be liable for civil penalties. It’s never gone that far, Cusson said. He wouldn’t say how many letters have gone out. HBO rarely goes out to find violators; lawyers usually send them once the network finds out about the promotions, usually through the newspaper.

A Chicago restaurant named Sopranos has resisted the temptation to play on the connection. The name predates the TV show.

“We’re the good guys,” said Georgia Demacopoulos, the restaurant’s general manager. “We follow the law. Everyone would come in and say to me, ‘Why aren’t you doing something with the show?’ I’d say we can’t, it’s illegal. And they say, ‘everyone else in the city is doing it.”‘

“Some of them are so blatant to even advertise it in the newspaper,” Demacopoulos said.

Ironically, Cusson said, HBO itself is planning some restaurant promotions for “The Sopranos” that will feature visits from cast members and they’ll bring a tape of the show with them.