Located in the Eastern (GMT -05:00) time zone. Area code 484 serves the state of Pennsylvania. This area code was assigned on July 31st, 1998. On June 5th, 1999 it went into service. 484 is a General Purpose Code. 484 service area does overlap with 610 area codes. Dialing pattern for local calls within the same NPA (area code) is 10D. All calls within and between the 215 and 267 and 484 and 610 NPAs can be dialed as 10D or 1+10D. Calls to other NPAs must be dialed as 1+10D.