310 Phone Area Code Goes Into Operation

About 2.4 million Los Angeles County telephone customers have a new area code this morning. A large chunk of southern and western sections of the county were scheduled to switch from the 213 area code to a 310 area code, phone company officials said.

The change, affecting a U-shaped swath from Malibu to Montebello, is needed to create an additional supply of phone numbers that will last the county until the year 2000, officials say.

Callers who forget to use the new area code will automatically be put through during a six-month transition period. Beginning next May, phone companies will activate a recording that will instruct callers to redial and use the new area code.