This numerical designation represents a specific geographic region within the North American Numbering Plan. It serves as a prefix dialed before a seven-digit local number to connect a telephone call to a subscriber within that defined area. As an example, when calling a number within this zone from outside of it, the sequence must be dialed prior to the local number.
The code is essential for efficient telephone routing and communication. It enables telecommunication networks to correctly direct calls to the intended destination. Its implementation simplified long-distance calling and facilitated the expansion of telephone services. The creation and assignment of these codes have played a vital role in the development of modern communication infrastructure.