Bell System Practices

Last updated
A typical volume of Bell System Practices from the 1970s. BellSystemPractices.jpg
A typical volume of Bell System Practices from the 1970s.

The Bell System Practices (BSPs) is a compilation of technical publications which describes the best methods of engineering, constructing, installing, and maintaining the telephone plant of the Bell System under direction of AT&T and Bell Telephone Laboratories. [1] Covering everything from accounting and human resources procedures through complete technical descriptions of every product serviced by the Bell System, it includes a level of detail specific to the best way to wrap a wire around a screw, for example.

Contents

With sections regularly updated, printed and distributed, the BSPs were the key to the standardized service quality throughout the Bell System. They enabled employees, who had never met previously, to easily work with one another in the event of a service outage, a disaster, or merely when relocating. Updates cover manufacturing changes phased into production during a product's lifetime of interest to the installer, including changed product features, internal component parts, available colors and installation procedures. Collectors also use these documents to help date and restore vintage telephones.

Document organization

Issuance of Bell System Practices within the Bell System started in the late 1920s, when they replaced a similar compendium, the AT&T Handbook Specifications. Initially, BSPs were identified by mixed alphanumeric sequence numbers designating a section and a specific document number within each section. The sections consisted of one letter and two digits, followed by a period character and a three-digit document number. The version of each document was indicated by an issue number. For example, the section designation C34.175 Issue 1 identified a document entitled Station Dials—2 and 4 Types—Maintenance.

In the 1950s, the format of BSP designations was changed to a nine-digit numerical format, written in three groups of three digits. The first three digits referred to the division, which indicated a broad subject area, such as subscriber sets or the No. 1 ESS. The next three digits indicated a specific subject area, such as the specific type of equipment used within the major division subject. The final three digits indicate the serial number of the document. The content could be general descriptive information, information on wiring and connections, test procedures, or piece-part replacement and repair information.

The BSP documents were produced in primarily two formats, 8 1/2"x11" pages for use in office environments, and in a small, portable format (4" x 6 7/8") for use by installers on the job, carried in their service trucks. Starting in the 1970s the most frequently used BSPs were bundled in convenient handbooks each covering general subject matters, such as the Station Service Manual.

The 9-digit format and numbering system was also used by Nortel and ITT Corporation due to their provenance from the Bell System's manufacturing unit, Western Electric.

Changes after divestiture

After the Bell System divestiture of 1984, AT&T maintained the basic organization and maintenance of the publication under the revised name AT&T Practices, but the publication was later divided among the new companies created by divestiture. Specifically, the AT&T Practices covered most equipment topics that stayed with Bell Labs, which acquired the name AT&T. Bellcore Recommendation covered network maintenance and design topics transferred to Bellcore. Bell Service Practices (and variations) referred to the plant and technical reference maintained by the various Regional Bell Operating Companies. Lucent Technology Practices, and other publications contained product lines taken over by the respective manufacturers. Avaya and Alcatel-Lucent still publish practices using the 9-digit section numbering format.

BSP nine-digit numerical index

Related Research Articles

<span class="mw-page-title-main">Bell Labs</span> Research and scientific development company

Bell Labs is an American industrial research and development (R&D) company credited with the development of radio astronomy, the transistor, the laser, the photovoltaic cell, the charge-coupled device (CCD), information theory, the Unix operating system, and the programming languages B, C, C++, S, SNOBOL, AWK, AMPL, and others. Ten Nobel Prizes and five Turing Awards have been awarded for work completed at Bell Laboratories.

<span class="mw-page-title-main">E.164</span> ITU-T Recommendation for telephone numbering

E.164 is an international standard, titled The international public telecommunication numbering plan, that defines a numbering plan for the worldwide public switched telephone network (PSTN) and some other data networks.

<span class="mw-page-title-main">North American Numbering Plan</span> Integrated telephone numbering plan of twenty North American countries

The North American Numbering Plan (NANP) is a telephone numbering plan for twenty-five regions in twenty countries, primarily in North America and the Caribbean. This group is historically known as World Zone 1 and has the telephone country code 1. Some North American countries, most notably Mexico, do not participate with the NANP.

A ringtone is the sound made by a telephone to indicate an incoming telephone call. Originally referring to the sound of electromechanical striking of bells or gongs, the term refers to any sound by any device alerting of an incoming call.

The Pacific Bell Telephone Company (Pac Bell) is a telephone company that provides telephone service in California. The company is owned by AT&T through AT&T Teleholdings, and, though separate, is now marketed as “AT&T”. The company has been known by a number of names during which its service area has changed. The formal name of the company from the 1910s through the 1984 Bell System divestiture was The Pacific Telephone and Telegraph Company. As of 2002, the name “Pacific Bell” is no longer used in marketing, although Pacific Bell is still the holder of record for the infrastructure of cables and fiber through much of California.

A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, reachable by a system of destination code routing. Telephone numbering plans are defined in each of the administrative regions of the public switched telephone network (PSTN) and in private telephone networks.

Seven-digit dialing is a telephone dialing procedure customary in some territories of the North American Numbering Plan (NANP) for dialing telephone numbers in the same numbering plan area (NPA). NANP telephone numbers consist of ten digits, of which the leading three are the area code. In seven-digit dialing it is not necessary to dial the area code. The procedure is also sometimes known as local format or network format.

<span class="mw-page-title-main">Area codes 202 and 771</span> Area codes for Washington, D.C.

Area codes 202 and 771 are telephone area codes in the North American Numbering Plan (NANP) for Washington, D.C.

VTech Innovation, L.P., doing business as Advanced American Telephones, is a telephone manufacturing company.

<span class="mw-page-title-main">Design Line telephone</span> Line of American telephones

Design Line, also known as Deco-Tel, is a brand name that AT&T has used for several of its specialty telephone designs to fulfill the demand by customers for more variety in telephone models.

Telecom Valley was an area located in Sonoma County, California specifically the Redwood Business Park of Petaluma, California.

A class-4, or tandem, telephone switch is a U.S. telephone company central office telephone exchange used to interconnect local exchange carrier offices for long distance communications in the public switched telephone network.

The Number One Crossbar Switching System (1XB), was the primary technology for urban telephone exchanges served by the Bell System in the mid-20th century. Its switch fabric used the electromechanical crossbar switch to implement the topology of the panel switching system of the 1920s. The first No. 1 Crossbar was installed in the PResident-2 central office at Troy Avenue in Brooklyn, New York which became operational in February 1938.

Notes on the Network is a publication of the American Telephone & Telegraph Company (AT&T) that outlines the state, technology, and operating principles of the public switched telephone network in the United States and Canada, and the other member regions of the North American Numbering Plan.

The No. 4 Electronic Switching System (4ESS) is a class 4 telephone electronic switching system that was the first digital electronic toll switch introduced by Western Electric for long-distance switching. It was introduced in Chicago in January 1976, to replace the 4A crossbar switch. The last of the 145 systems in the AT&T network was installed in 1999 in Atlanta. Approximately half of the switches were manufactured in Lisle, Illinois, and the other half in Oklahoma City, Oklahoma. At the time of the Bell System divestiture, most of the 4ESS switches became assets of AT&T as part of the long-distance network, while others remained in the RBOC networks. Over 140 4ESS switches remained in service in the United States in 2007.

A specification often refers to a set of documented requirements to be satisfied by a material, design, product, or service. A specification is often a type of technical standard.

<span class="mw-page-title-main">Telephone number</span> Sequence of digits assigned to a telephone subscription

A telephone number is a sequence of digits assigned to a landline telephone subscriber station connected to a telephone line or to a wireless electronic telephony device, such as a radio telephone or a mobile telephone, or to other devices for data transmission via the public switched telephone network (PSTN), or other public and private networks. Modern smart phones have added a built-in layer of abstraction whereby individuals or businesses are saved into a contacts application and the numbers no longer have to be written down or memorized.

<span class="mw-page-title-main">Bell System</span> American telephone service monopoly (1877-1982)

The Bell System was a system of telecommunication companies, led by the Bell Telephone Company and later by the American Telephone and Telegraph Company (AT&T), that dominated the telephone services industry in North America for over 100 years from its creation in 1877 until its antitrust breakup in 1983. The system of companies was often colloquially called Ma Bell, as it held a vertical monopoly over telecommunication products and services in most areas of the United States and Canada. At the time of the breakup of the Bell System in the early 1980s, it had assets of $150 billion and employed over one million people.

<span class="mw-page-title-main">Telephone exchange</span> Interconnects telephones for calls

A telephone exchange, also known as a telephone switch or central office, is a crucial component in the public switched telephone network (PSTN) or large enterprise telecommunications systems. It facilitates the interconnection of telephone subscriber lines or digital system virtual circuits, enabling telephone calls between subscribers.

In the North American Numbering Plan (NANP), interchangeable NPA and central office codes constituted a change in numbering plan design and policy, to mitigate exhaustion of the numbering resources of the ten-digit telephone numbers used in the closed numbering plan of the NANP.

References

  1. ↑ A.B. Covey, The Bell System's Best Sellers, Bell Telephone Magazine, Summer 1952, Pages 87—95 (AT&T)
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.