A sequence of digits used to contact a specific subscriber within the southeastern Pennsylvania region. This identifier adheres to the North American Numbering Plan and consists of an area code, a central office code, and a subscriber number. For example, a valid sequence might begin with the area code 215, followed by a three-digit exchange, and conclude with a four-digit individual line number.
These identifiers are essential for both residential and commercial communication within the city and its surrounding areas. Their proper allocation and management are crucial for ensuring effective connectivity and facilitating economic activity. Historically, the assignment and usage of these identifiers have evolved alongside technological advancements in telecommunications, reflecting the growth and changing demographics of the metropolitan area.