Centrex Line

Assignments and Ringing

Your local telephone company provides a block of Centrex lines that are used with your telephones. When you connect these lines to your equipment controller and supply electrical power, the controller automatically assigns one Centrex line to each extension. The only exception is the phone connected to extension jack 10, which is assigned all of the lines in your system, to permit a receptionist to answer calls for users if they do not pick up immediately. (For more information on call coverage, see “Call Coverage Options” in Chapter 4.)

By default, the primary line for an extension is set for immediate ringing and any secondary lines are set for delayed ringing. When a call comes in on a line, it rings immediately at the extension where the line is assigned as a primary line; after about 20 seconds it also begins to ring at any extensions where the line is assigned as a secondary line (for example, at the receptionist’s extension).

NOTE:

The equipment controller passes Centrex ringing patterns through to each phone (for example, Centrex ringing patterns are usually different for outside and inside calls).

Centrex Line and Extension Numbers

Each Centrex line is identified by a seven-digit telephone number (for example, 555-1212). When someone outside your system calls a Centrex telephone number (an outside call), the call rings at the extension where that number is assigned as the primary line.

Users who are on the same Centrex system can generally dial another extension (an inside call) using the Centrex extension number. The Centrex extension number is typically the last digits of the telephone number—the number of digits is determined by the local telephone company, but in most cases the last four or five digits of the telephone number are used. For example, the Centrex extension number for 555-1212 might be 1212 or 51212. (Some Centrex systems may also provide a one-or two-digit “Centrex extension ID” that can be used to dial other extensions.)

Jack Numbers for Extensions and Lines

Although users will identify extensions by the Centrex extension number, the equipment controller tracks lines and extensions using two other numbers, based on the physical connections at the equipment controller. When your premises equipment was installed (see Chapter 2), the following connections were made:

Each Centrex line comes into your building from your local telephone company and terminates at a network interface jack; each network interface jack is then connected to a line jack on the equipment controller. Each line jack on the controller is identified by a line jack number. Line jack numbers run from 01 through 24 (if you have the maximum number of lines that can be used with your premises equipment).

Using the Equipment 3-3

Page 43
Image 43
AT&T II Centrex Line Assignments and Ringing, Centrex Line and Extension Numbers, Jack Numbers for Extensions and Lines

II specifications

AT&T II, a pivotal case in the landscape of telecommunications regulation, emerged from the expansive antitrust actions against the American Telephone and Telegraph Company (AT&T). Following World War II, AT&T had established itself as a telecommunications behemoth, monopolizing the market. The ramifications of this dominance spurred a significant shift in regulatory measures, leading to the dissolution of the Bell System in 1984, which consisted of AT&T and its regional operating companies.

One key feature of AT&T II is its emphasis on promoting competition in the telecommunications sector. The court's decision aimed to dismantle the monopolistic practices that had stifled innovation and restricted consumer choice. By encouraging competition among various service providers, the ruling paved the way for an environment where new technologies could flourish.

The technologies that emerged post-AT&T II significantly transformed the telecommunications landscape. The introduction of new digital switching systems allowed for improved call quality and increased network efficiency. The evolution of fiber-optic technology also played a crucial role, enabling faster transmission speeds and greater data capacity. Moreover, innovative services, such as mobile telephony and broadband internet, proliferated as competition increased.

Another characteristic of AT&T II is its focus on accessibility and consumer protection. The ruling mandated that telecommunications services be available to a broader swath of the population, ensuring that underserved communities had access to essential communication services. This shift not only democratized access but also laid the groundwork for the modern internet revolution, fostering the growth of the digital economy.

The impact of AT&T II can also be seen in the regulatory frameworks that followed. The Federal Communications Commission (FCC) adopted policies aimed at enhancing market transparency and ensuring fair practices among competitors. These regulatory changes helped to create a more equitable playing field, allowing smaller companies to compete against established giants.

In summary, AT&T II marked a turning point in telecommunications history, characterized by a focus on competition, technological advancements, and consumer protection. The dissolution of AT&T's monopoly allowed for the rapid evolution of technology and services, ultimately benefiting consumers and fostering an environment ripe for innovation. This ruling not only redefined the telecommunications industry but also set a precedent for how markets are regulated in the United States.