The Switching Control Center System was an operations support system developed by

Bell Laboratories Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial Research and development, research and scientific developm ...

and deployed during the early 1970s. This

computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations ( computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These prog ...

system was first based on the

PDP-11 The PDP-11 is a series of 16-bit minicomputers sold by Digital Equipment Corporation (DEC) from 1970 into the 1990s, one of a set of products in the Programmed Data Processor (PDP) series. In total, around 600,000 PDP-11s of all models were sol ...

product line from

Digital Equipment Corporation Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president un ...

and used the CB Unix

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...

and custom

application software Application may refer to: Mathematics and computing * Application software, computer software designed to help the user to perform specific tasks ** Application layer, an abstraction layer that specifies protocols and interface methods used in a ...

and device drivers that were developed and maintained by

Bell Labs Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mul ...

Columbus, Ohio Columbus () is the state capital and the most populous city in the U.S. state of Ohio. With a 2020 census population of 905,748, it is the 14th-most populous city in the U.S., the second-most populous city in the Midwest, after Chicago, an ...

USA. SCCS was ported to the AT&T 3B20 and 3B5 computers running

UNIX System V Unix System V (pronounced: "System Five") is one of the first commercial versions of the Unix operating system. It was originally developed by AT&T and first released in 1983. Four major versions of System V were released, numbered 1, 2, 3, an ...

Release 2 in the early 1980s. Prior to the SCCS, many

telephone company A telephone company, also known as a telco, telephone service provider, or telecommunications operator, is a kind of communications service provider (CSP), more precisely a telecommunications service provider (TSP), that provides telecommunicat ...

switching centers were staffed 24 hours a day 365 days a year. With SCCS, telephone companies could significantly reduce the number of technicians and dispatch them as required to resolve problems or perform routine maintenance operations. During the early 1970s, telephone companies began to phase out the older electromechanical switching systems such as the Number 1 Crossbar, Number 5 Crossbar, and

step-by-step Step by Step may refer to: Film and television * ''Step by Step'' (1946 film), an American film directed by Phil Rosen * ''Step by Step'' (2002 film), a Belgian film directed by Philippe Blasband * ''Step by Step'' (TV series), a 1990s Americ ...

circuit switching systems and replace them with newer electronic switching systems that were controlled by proprietary computers but still used analog switch fabrics such as Bell-proprietary ferreed switch devices. The SCCS system was phased out during the late 1990s and replaced by an

OSS OSS or Oss may refer to: Places * Oss, a city and municipality in the Netherlands * Osh Airport, IATA code OSS People with the name * Oss (surname), a surname Arts and entertainment * ''O.S.S.'' (film), a 1946 World War II spy film about ...

known as Network Monitoring and Analysis or NMA that was developed by

Bell Communications Research iconectiv is a supplier of network planning and network management services to telecommunications providers. Known as Bellcore after its establishment in the United States in 1983 as part of the break-up of the Bell System, the company's name ...

now Telcordia Technologies. AT&T developed additional products based on SCCS software, such as Compulert. The primary purpose of the SCCS system was to provide operations,

administration Administration may refer to: Management of organizations * Management, the act of directing people towards accomplishing a goal ** Administrative Assistant, traditionally known as a Secretary, or also known as an administrative officer, admini ...

maintenance Maintenance may refer to: Biological science * Maintenance of an organism * Maintenance respiration Non-technical maintenance * Alimony, also called ''maintenance'' in British English * Champerty and maintenance, two related legal doct ...

, and

provisioning In telecommunication, provisioning involves the process of preparing and equipping a network to allow it to provide new services to its users. In National Security/Emergency Preparedness telecommunications services, ''"provisioning"'' equates to ...

(

OAMP Operations, administration and management or operations, administration and maintenance (OA&M or OAM) are the processes, activities, tools, and standards involved with operating, administering, managing and maintaining any system. This commonly ...

) functions for

network operations staff. The SCCS accepted as input the slow 110

baud In telecommunication and electronics, baud (; symbol: Bd) is a common unit of measurement of symbol rate, which is one of the components that determine the speed of communication over a data channel. It is the unit for symbol rate or modulat ...

Teletype A teleprinter (teletypewriter, teletype or TTY) is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. Init ...

messages from circuit switching systems such as the Number 1 ESS, Number 2 ESS, Number 3 ESS, Number 5 ESS, and Traffic Service Position System (

TSPS The Traffic Service Position System (TSPS) was developed by Bell Labs in Columbus, Ohio to replace traditional cord switchboards. The first TSPS was deployed in 1969 and used the Stored Program Control-1A CPU, "Piggyback" twistor memory (a propr ...

) network switches and provide analysis, reports, troubleshooting support, and other functions using newer faster DataSpeed-40 terminals. This system was documented in the Bell System Technical Journal and

AT&T AT&T Inc. is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the world's largest telecommunications company by revenue and the third largest provider of mobile ...

internal

Bell System Practices 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 ...

during the 1970s.

References

{{reflist Telephony