"E" is Eastern Time Zone, "C" is Central Time Zone, "M" is Mountain Time Zone, and "P" is Pacific Time Zone. Occasionally, an area code will fall in more than one time zone. In this case, the abbreviation is a combination of the previous abbreviations. Some area codes are shown with time zones referencing Universal Coordinated Time (UTC).
Additional technical status can be retrived from the North American Numbering Plan Administration on the 818 area code specific link here.
Area code 818 went live into service on January 07, 1984.  It was formed as a subdivision of the 213 area code.  It has had the 747 area code(s) overlaid on it.
This area code went live on January 07, 1984 as an "overlay" on the 747 area code. This means the 818 area code was created in part to provide more telephone numbers for people in the 747 area code area. In other words, 818 is a subdivision of the 747 area code. Due to popularity, this area code is starting to run out of free telephone numbers for people to use which means that this area code is technically referred to as being "in jeoparady." Planning is underway and notices have been distributed regarding the area code subdivision.
NO HOLLYWD, RESEDA, VAN NUYS, CANOGAPARK, LSAN DA 01, BRBN BRBN, GLENDALE, SNFN GRHL, SNFN SPLV, SNFN SNFN, LACRSCENTA, BRBN SNVY, SNFN PACM, SUNLD TJNG, NORTHRIDGE, AGOURA, PSDN LACN, DIR ASST
Number of major cities served
Names of major cities served (ZIP code)
North Hollywood (91605), N Hollywood (91605), Los Angeles (91335), Encino (91335), Reseda (91335), Tarzana (91335), Van Nuys (91405), Valley Glen (91405), Van Nuys (91403), Sherman Oaks (91403), Calabasas (91302), Woodland Hills (91302), Hidden Hills (91302), Monte Nido (91302), Woodland Hls (91302), Los Angeles (90071), Arco (90071), Arco-plaza (90071), Burbank (91502), Anaheim (92805), Federal (92805), Glendale (91204), Northridge (91343), North Hills (91343), Sepulveda (91343), Canoga Park (91303), Woodland Hills (91303), Woodland Hls (91303), San Fernando (91340), Glendale (91214), La Crescenta (91214), Northridge (91324), Agoura Hills (91301), Calabasas (91301), Oak Park (91301), Agoura (91301), Calabasas Hills (91301), Calabasas Hls (91301), Cornell (91301), Saratoga Hills (91301), Saratoga Hls (91301), Sunland (91040), Shadow Hills (91040), Los Angeles (90001), Firestone Park (90001), Firestone Pk (90001), La Canada Flintridge (91011), Flintridge (91011), La Canada (91011), La Canada Flt (91011), San Fernando (91344), Granada Hills (91344), Sylmar (91342), Kagel Canyon (91342), Lake View Ter (91342), Lake View Terrace (91342), Los Angeles (90017), Foy (90017), North Hollywood (91601), Valley Village (91601), N Hollywood (91601), Toluca Ter (91601), Toluca Terrace (91601), Valley Vlg (91601), Agoura Hills (91377), Oak Park (91377), Burbank (91504), Chatsworth (91311), Thousand Oaks (91362), Westlake Village (91362), Westlake Vlg (91362), Los Angeles (91331), Pacoima (91331), Arleta (91331), Hansen Hills (91331), Lakeview Terrace (91331), (00000)
45 telephone companies servicing the 818 area code
List of telephone companies
O1 COMMUNICATIONS, INC. - CA, NEXTEL COMMUNICATIONS, INC., MPOWER COMMUNICATIONS CORP - CA, USA MOBILITY WIRELESS, INC., NEW CINGULAR WIRELESS PCS, LLC, PACIFIC BELL, PAETEC COMMUNICATIONS, INC. - CA, T-MOBILE USA, INC., BROADWING COMMUNICATINS. LLC - CA, SPRINT SPECTRUM L.P., TW TELECOM OF CALIFORNIA LP - CA, CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA, COOK TELECOM, INC., INFOTELECOM, LLC - CA, VERIZON CALIFORNIA INC.-CA (GTE), XO CALIFORNIA, INC., GLOBAL CROSSING LOCAL SERVICES, INC.-CA, PAC - WEST TELECOMM, INC., LEVEL 3 COMMUNICATIONS, LLC - CA, NETWORK SERVICES LLC, TELEPORT COMMUNICATIONS GROUP - LOS ANGELES, PACIFIC BELL - CLEC, AT&T LOCAL, ALLEGIANCE TELECOM, INC. - CA, 360NETWORKS (USA) INC. - CA, AMERICAN MESSAGING (AM), INC., MCIMETRO ACCESS TRANSMISSION SERVICES LLC, DIGITCOM SERVICES, INC., ROYAL STREET COMMUNICATIONS, LLC, PLANET TELESIS, INC. - CA, CBEYOND COMMUNICATIONS, LLC - CA, MCI WORLDCOM COMMUNICATIONS, INC., CA, U.S. TELEPACIFIC CORP. - CA, TELCENTRIS COMMUNICATIONS, LLC - CA, CURATEL, LLC - CA, SPRINT COMMUNICATIONS COMPANY, L.P. - CA, THE TELEPHONE CONNECTION OF LOS ANGELES, INC., POINTE COMMUNICATIONS CORP. - CA, YMAX COMMUNICATIONS CORP. - CA, PACIFIC CENTREX SERVICES, INC. - CA, NORTH COUNTY COMMUNICATIONS CORP. - CA, CROWN CELLULAR & PAGING, COST PLUS COMMUNICATIONS, LLC - CA, SHELCOMM, PG TELECOM OF CALIFORNIA INC. - CA