THE PREFIX IS IN

To some people on the Westside and in the South Bay, 310 is more than just an area code.

It’s a geographic marker -- one that many associate with wealth, glamour and the beach.

“It stirs up feeling of ‘Ah, Ooh.’ You always have great expectations,” said Larry Steele, who with his partners recently christened their new Santa Monica restaurant 310 Lounge & Bistro. “It’s a hot name.”

It may soon be an unavailable name.

State officials are considering a plan that would create California’s first area code overlay. If approved, new phone customers within the boundaries of 310 probably would receive a new area code: 424.

That means that all customers within the 310 would have to dial an area code before the number -- and that neighbors could have different area codes.

Though new to the state, there are nearly 50 area code overlays nationwide, including in New York City and 15 states. Atlanta alone has three area codes overlapping one another.

The overlay is the latest plan in a seven-year-long battle between the telephone industry and local communities over whether the 310 is running short on numbers and needs a new area code.

Phone providers and the California Public Utilities Commission insist that cellphones, fax machines, Blackberries, ATM and home computer modems are quickly devouring 310 numbers. Residents and businesses insist that there are enough numbers to go around and that providers are exaggerating the shortage.

The latest plan has met with concern across the largely upscale zone, which extends from the Palos Verdes Peninsula up the coast to Santa Monica and Malibu, then east through Brentwood, Westwood, Century City and Beverly Hills.

To critics, the 424 overlay would cause confusion, not to mention the inconvenience of dialing 11 digits for every call.

But many also fear that dual area codes would erase part of the region’s identity.

“The area code is like your street address; you get attached to it,” said Santa Monica resident Steve Chapek, 34, as he worked the counter at California Map & Travel Center. “If they keep adding area codes like that, you won’t have any sense of a neighborhood.”

Some go to great lengths to get a 310 area code, feeling it provides them a certain cachet even if they don’t live within its boundaries.

Vonage, an Internet phone company that allows users to select 310 phone numbers regardless of where they live, said it has seen a particular run on numbers based in Beverly Hills.

“It’s a cultural thing,” said Vonage spokeswoman Brooke Schulz. “If you are an actor or an agent, you want to have a 310, because 310 is synonymous with the area of Santa Monica, Brentwood, Beverly Hills -- all these places that have cachet in Los Angeles. When you have that 310 number, it says something about you.”

Indeed, the founders of a post-production visual effects company decided to keep its name 310 Studios, President Billy Jones said, even though its offices opened in Burbank, in the 818 area code.

Area codes have long been a cultural identifier in Southern California, for better or worse. In the movie “Swingers,” characters rated date prospects on the virtue of their area codes (they found the 310 more impressive than the San Fernando Valley’s 818). Radio deejays and TV shows frequently poke fun at the Inland Empire’s 909 area code, associating it with the unsophisticated boondocks.

Some experts roll their eyes at the passionate efforts to keep the 310 area code the way it is.

A. Michael Noll, a professor at the USC Annenberg School for Communication, said some residents in tony enclaves wrongly believe the area code makes some profound statement about where they live and who they are.

To them, the area code “has a lot of social status,” he said.

In reality, the 310 takes in some working-class communities, including Compton, Lawndale, Hawthorne and Lynwood.

Noll said that when the phone company in the 1950s introduced the current seven-digit numerical dialing, it received protests from people who preferred the old system, which used names like “Webster” and “Olive” to denote the first few digits of a phone number. “They felt some prefixes noted a more upscale neighborhood,” he said.

It’s the very popularity of the 310 that is fueling the overlay plan. The PUC said about 5.32 million numbers have been used or are otherwise unavailable, and that 1.97 million are left.

Until recently, phone carriers have wanted the state to split the 310 -- letting the Westside keep its area code and giving 424 to the South Bay. But faced with opposition, the companies have now asked the utilities commission to consider the overlay.

Under the proposal, which the PUC is considering, the overlay would be automatically triggered whenever the number of unused 310 prefixes -- sets of 10,000 available phone numbers -- dips to six sets. There are currently eight unused prefixes, though officials aren’t sure how long it would take to drop to six.

But this plan is proving just as unpopular as the split idea.

“I don’t want to have to dial [11] numbers every time I make a phone call,” Chapek said.

His boss, Jon Eckstrom, was equally skeptical. He cited a classic episode of the TV show “Seinfeld,” in which Elaine gets stuck with Manhattan area code 646, which is an overlay of the more familiar 212 area code. That prompts a man to reject her for a date because he believes she lives in New Jersey, not Manhattan. Elaine ends up obtaining a dead neighbor’s phone number to get back a 212 area code.

“310 represents Santa Monica. 424 or other area codes wouldn’t,” said Jory Wolf, who oversees information technology and telecommunications issues for the city of Santa Monica. “If we wanted new numbers for the Fire Department, we might get an overlay number, which we think would be very confusing to people.”

Jack Leutza, director of the PUC’s telecommunications division, said that he understood people didn’t like change, but that they needed to appreciate that the shortage of telephone numbers was real.

“People really do not like to change numbers. But the need to split an area code means the area in question is growing, and it has got an active economy, and it demands more telephone numbers,” he said. “We’re really close to number exhaust.”

The overlay plan appeals to some in the South Bay who don’t want to lose the 310 area code altogether. One is Thomas Megallon, who owns 310 Tattoo & Body Piercing, which is at 310 W. Pacific Coast Highway in Wilmington and has a 310 phone number.

Even at conventions, he tries to get a 310 booth number.

“Everything is 310,” said Megallon, who proudly explained how it was easy for his customers to remember his address. “We made [the name] for the address number, so we came out perfect.”

There remains heavy skepticism that another area code is really needed. When the PUC moved to implement the idea in 1999, the South Bay and the Westside successfully fought it. Opponents were buoyed when officials revealed several months later that at least 3 million phone numbers were still available in the 310, and that phone carriers held on to an unknown quantity of phone numbers for future use.

“Lo and behold, the system was being gamed. There were plenty of numbers left,” said Redondo Beach City Councilman John Parsons, who has been fighting against a new area code since the late 1990s.

A coalition of South Bay cities has joined to oppose the overlay proposal, warning that because the state relies heavily on the industry to project its own demand for phone numbers, it could be easy for carriers to stockpile their supply and thus automatically trigger a new area code when it’s not needed.

They also support a bill by Assemblyman Mike Gordon (D-El Segundo) that supporters say would make it more difficult for phone companies to stockpile phone numbers. (The Assembly approved the legislation last week.)

Carriers insist the 310 can’t last forever.

Said T-Mobile spokeswoman Susan Lipper: “The finite nature of math is catching up with us.”