Next month telephone customers in the 510 area code must dial 1 plus the area code and the number to make any call to the 510 or the new 341 area code, according to the California Public Utilities Commission.
The new dialing procedure starts June 22 and paves the way for the addition of the 341 area code to the region served by the 510 code. The changes do not require anyone to change their phone number.
Consumers with a 341 area code must also dial 1 plus the area and telephone number, CPUC officials said. Cellphones automatically recognize an out-of-area number and automatically add a 1 to the number during the dialing process.
The price of calls will remain unchanged. Calls that are in a consumer's local calling area will still be local calls.
Consumers must reprogram automatic dialing systems for such equipment as life safety systems and medical monitoring devices, internet dial-up numbers, fax machines, gates, alarm and security systems, speed dialers, voicemail, call forwarding systems and similar equipment.
CPUC officials said consumers can still dial just 911 for an emergency and calls to similar numbers like 211, 311, and 411 can be dialed just using those three numbers.
Beginning June 22, people requesting a new phone number will be assigned either a 510 or 341 number.
More information is available online or from the consumer's telephone service provider.