773

Area code 773 is a significant telephone area code in the United States, primarily serving Chicago, Illinois. Geographic Coverage: Area code 773 serves Chicago, Illinois, specifically areas outside the Loop and the innermost neighborhoods. It's important to note that originally, all of Chicago and its suburbs were under area code 312. Later, in 1989, area code 708 was created for the suburbs, leaving the central city within area code 312​​. Time Zone and Service Area: The 773 area code is located in the state of Illinois and primarily serves its largest city, Chicago. It operates under the Central Standard Time (CST) zone. When Daylight Saving Time is observed, the time difference changes accordingly, aligning with the standard practices of time zone adjustments in the United States​​. History and Implementation: The 773 area code was assigned on February 29, 1996, and officially went into service on October 12, 1996. It is classified as a General Purpose Code. The area covered by the 773 code overlaps with the 872 area codes. The standard dialing pattern for local calls within the same Numbering Plan Area (NPA) is 1+10 digits​​. In conclusion, the 773 area code is an integral part of the telecommunication infrastructure in Chicago, Illinois. It serves a significant portion of the city, operates in the CST time zone, and has a history dating back to 1996, marking its importance in the region's communication network.