A Telephone Numbering Plan is a system that organizes how telephone numbers are assigned and formatted within a specific region or country. It ensures that each number is unique and helps manage the allocation of numbers to different service providers. This plan typically includes area codes, which identify geographic regions, and subscriber numbers, which are unique to each individual or business. The numbering plan also defines the length of phone numbers and any special codes for services like emergency calls. By standardizing these elements, the Telephone Numbering Plan facilitates efficient communication and helps prevent confusion among users.