In telecommunications, a telephone-numbering plan serves as a type of numbering scheme used to allocate telephone numbers to subscriber telephones as well as any other telephony endpoints. Phone numbers are the addresses of subscribers on a telephone network that are reachable via a system for forwarding destination codes. There are plans of telephone numbering for each administrative region of the public switched telephone network (PSTN) as well as in private telephone networks. When it comes to public numbering systems, where a user is geographically located determines the order of numbers given to each telephone subscriber.
The service area for many numbering plans is divided into geographic regions that are identified by a prefix, most commonly referred to as the area code or city code. An area code is a sequence of digits that represents the most important part of the dialing process required to reach a telephone subscriber.
What does North American Numbering Plan mean?
One of the most important of these plans is the North American Numbering Plan (NANP), which is a unified telephone numbering plan managed by NeuStar, previously known as Lockheed Martin IMS. This plan covers 24 countries as well as territories, which includes the United States and its territories, Bermuda, Canada, and 17 states in the Caribbean. Besides, the metonymic usage of the term refers to the geographic region where the plan was implemented.
As a standardized system of numbering plan areas (NPAs), the NANP evolved through time as a system of three-digit area codes as well as seven-digit telephone numbers. According to this plan, phone calls can be routed to specific areas of the larger NANP public switched telephone network (PSTN), and then the local networks forward these calls. Visit Ara Ara’s website, to search for phone area codes by state or number, or if you want to discover anything about a particular area code.
Origin of the North American Numbering Plan
Bell system managers developed a new method of dialing phones during the mid-20th century as a result of the fast-growing telephone network in the United States. Before that time, human operators had been the ones who routed calls to their intended destinations. At the time, the North American numbering plan deployed by the Bell System that started in the 1940s was intended to take the place of a more complex system that involved operators manually routing calls through the system. The phone company was trying to allow people to call anyone, from anywhere, using an automated method.
First developed in the 1940s, the NANP was implemented by AT & T in 1951. Its purpose was to make direct dialing of long-distance calls simpler and easier. Area Code 201 became the first code that was implemented under the plan. Originally, the NANP operated only in the U.S. and Canada, later it was extended to Bermuda and the British West Indies upon the request of the British Colonial Office. The reason for this was their historical telecommunications administration by Canada as parts of the British Empire.
However, this system was slowly evolving. In 1955, AT&T, while trying to find solutions to reduce confusion regarding spoken telephone directions, provided a recommended list of interchange names with standardized shortcuts. Bell’s engineers had been doing their analysis of the scalability concerning the system of name and number. Indeed, one of their intentions was to extend the national telephone network. According to their own research, Bell had found that the country was unable to provide a sufficient number of employees to satisfy the rising demand for human operators. Bell concluded that automation represented the future of telephony. What’s more, the path to this new era of automation included the use of numbers only and no more names.
Area code expansion
In particular, during the period from 1990 to 2005, Canada and the United States both achieved a rapidly growing number of area codes. That was mainly due to two factors. To begin with, there has been a growing consumer demand for telephone services, owing to the widespread deployment of modem, fax, and cell phone communications.
Its second and more significant factor is the deregulation of the telecommunication of local telephone service throughout the U.S., which started from the early to the mid-nineties. During that period, the Federal Communications Commission became involved in allowing telecommunications operators to compete with the incumbent local exchange carrier. Owing to the initial concept of the numbering plan as well as the telephone-switching network, under which only a single provider was assumed, the number allocations were required to be implemented in blocks of 10,000 numbers.
Generally, area codes came either as splits which involved dividing an area code within two or more regions, with one keeping the older area code and the other region getting a new area code, or as overlays. There were also subtle versions of these kinds of techniques used, such as dedicated overlays whereby the new overlay code remained in reserve for a specific type of services, such as mobile phones and pagers.
Once the remaining valid area codes were exhausted by expansion due to the rapid growth in the demand for more area codes, in 1995 NANPA forced the usage of digits 2 through 8 as the middle digit in the new area code assignments while reserving 9 in the event of future expansion. Meanwhile, it was permitted for local exchanges to use 1 or 0 as the middle digit. Codes that end in double digits are reserved as easily recognizable codes (ERCs), which are intended for specific purposes.
In fact, the purpose of area codes was to find an easier way of direct dialing of long distances phone calls. While some countries hold one area code, others have multiple. As years passed, the demand for more phone numbers has grown, resulting in the need for more area codes to be added. Once particular areas use up all the phone number variations in that area code, then an overlay will be added. In fact, an overlay area code is simply an extra area code that is assigned to a geographic region.