The Definity was the last in a line of circuit based PBX hardware manufactured since the late 1980s by Avaya

Avaya

Avaya Inc. is a privately held computer networking, information technology and telecommunications company that is a global provider of business communications systems. The international head quarters is in Basking Ridge, New Jersey, United States...

, then the former Enterprise Networks division of Lucent and AT&T's

AT&T

AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...

 Information Systems unit. The original Definity servers and switches can be enabled to use some versions of Avaya's later Communication Manager (now known as the Aura) software by using a Media Server to control a Definity switch (or a media gateway in recent releases). The Definity/Communication Manager has about 700 telephony

Telephony

In telecommunications, telephony encompasses the general use of equipment to provide communication over distances, specifically by connecting telephones to each other....

 features, one of the largest feature-sets compared to a Nortel Meridian

Nortel Meridian

Nortel Meridian is a private branch exchange. It provides advanced voice features, data connectivity, LAN communications, computer telephony integration , and information services for communication applications ranging from 60 to 80,000 lines.-History:...

, NEC's

NEC

, a Japanese multinational IT company, has its headquarters in Minato, Tokyo, Japan. NEC, part of the Sumitomo Group, provides information technology and network solutions to business enterprises, communications services providers and government....

 NEAX or Cisco's

Cisco Systems

Cisco Systems, Inc. is an American multinational corporation headquartered in San Jose, California, United States, that designs and sells consumer electronics, networking, voice, and communications technology and services. Cisco has more than 70,000 employees and annual revenue of US$...

 CallManager.

History

The Definity name began in the late 1980s/early 1990s to replace the System 75 and System 85 branding. A product page on Lucent's website circa 1998 referred to the Definity as "Definitive Solutions for an Infinite Number of Possibilities" allegedly referring to the name of the system. The Definity system was based on a terminal user interface with real English commands (i.e. "change station 1000" to change the settings for extension 1000), with step by step call processes called "vectors" with Logo like programming commands.

System 85 would be renamed as the Definity Communications System Generic 2 and the System 75 would be broken up into two separate models. For the Intel based system the system was renamed as Definity Communications System Generic 1 (G1) and a RISC based system that would become G3r. The Definity releases in the 1990s would support native ISDN technology, as a growing standard in digital telephony.

Between Generic 2 (G2) and Generic 3 (G3), the G2 was a larger system with more call coverage, a larger dial plan, and more telephones can be connected to the G2 switch. However, many years later in later releases of the Communication Manager, the dial plan, the telephones connected, and attendant coverage caught up with the old G2 (System 85). The G2/System 85 was built for very reliable voice communications, and the system was built on top of a legacy architecture before data communications, modern personal computers, or Internet abilities. The G2's legacy can be traced back to the mid 1970s when the AT&T Dimension was in place. When the System 85 was released about a decade after, the system was retooled from the old PCM/analog architecture to a digitally switched system.

In the late 1990s, the Generic 3 (the then System 75) became the new architecture for the Definity system, rebadged as the Definity Enterprise Communications Server (ECS). The G3 was the least system with legacy bloat, with the system being digitally based . A stripped-down model that was similar to the ECS was called the Definity Business Communications System (BCS), was targeted towards hotels and such. Version numbering on the ECS continued from the Definity G3r numbering, with the first branded release under ECS as Release 5 and continued as ECS Release 10 in 2001.

Hardware and software

The Definity servers prior to Communication Manager use a proprietary operating system called Oryx/Pecos

Oryx/Pecos

Oryx/Pecos is a proprietary operating system developed from scratch by Bell Labs beginning in 1978 for the express purpose of running AT&T's large-scale PBX switching equipment...

. The call processing, tone clocks, trunk and phone terminal connections as well as other digital processing technologies were processed through circuit cards to ensure reliable telephone conversations. The most used setups for a Definity based system would range from small colleges, hospitals, public safety, large corporations or government, department stores, and specific locations that use call centers, because of the programming and administration and user interface that can meet a need for call center applications.

The Definity switches through the respected variants of the systems for many years sold either in a single carrier cabinet (SCC) or a multi carrier cabinet (MCC.) SCC had about 14 slots and a user count up to about 120, and could be daisy chained to up to 5 carriers per node to about 450 users total per node. The MCC worked as a large mainframe

Mainframe computer

Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...

, premise based carrier switch. The MCC contained about 200 slots for a total about 650 users per node. (In Aura Release 5, the SCC and MCC are officially discontinued for software support, with requirement to use a rack formed media gateway similar to the SCC.)

The primary switching unit was the Processor Port Network (PPN) that handled the Oryx/Pecos, and other essential services for the system. For satellite locations within a campus or elsewhere, an Expanded Port Network (EPN) would be used. This would act as a dumb switch, requiring the PPN to operate most of all the features. The respected switching unit could be used on a respective MCC/SCC carriers.

The voice mail system is known as AUDIX

AUDIX

AUDIX is a Voicemail server intended to be used with Lucent/Avaya PBXes. It features many integrations with Avaya's PBXes, such as capturing the extension of the calling party and pronouncing that person's name when announcing the attributes of a message,...

 (or the Audio Information Exchange.) This was a precursor to modern unified messaging, first used on the System 75 and 85 systems. The AUDIX can handle messages between fax, voice and emails. The AUDIX name is still well known through the voice prompts, even though it is branded as other names, such as Intuity Audix or Modular Messaging. It's also known that an everyday phone user would refer a Definity system as "AUDIX" even though the systems operate separate things.

The Communication Manager/Aura powered systems now use Linux

Linux

Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

 as the operating system. Administrators can still access the traditional user friendly terminal administration, or use the web based administrative software, or use a desktop GUI program, the Avaya Site Administration (ASA). Linux knowledge is needed in some ways to configure the gateways and other new appliance-based equipment that used to be traditional carrier equipment.

Because the CM-based systems now run on appliance-based equipment, the same idea of PPN and EPN is still the same. For the main call processing and services, an Enterprise Survivable Server (ESS) would be installed at the primary location of the system. If an event the ESS fails, a Local Survivable Processor (LSP) would be installed in locations that can operate the basic telephony services till the ESS is restored. This can be used for redundancy (like the older systems) or for disaster recovery.

The long time protocol that the Definity telephones use to connect to the switch is called the Digital Communication Protocol or DCP. In later releases of Communication Manager, the system was reworked as SIP being the primary system-wide signaling protocol, while all previous legacy protocols would run under SIP.

Version Numbering

After Definity ECS Release 10 (late 2001 under Avaya), the system was redesigned as a software based telephony system and was rebadged under different names such as MultiVantage to the Communication Manager to now the current name, Aura (CM Release 5) as of 2010. At the time with a new system, would also start with new release numbers likely because it was the first IP based system to attract less skilled telephony managers or IT managers. While newer releases started in single digits, the system's numbers continued from the G3r release numbering from the legacy systems. Traditional Definity technicians may still refer by a legacy version. For example, modern version of the Communication Manager R 3.1 could also be read as G3rV13.1. Also, the legacy versions can be looked up through the terminal administration through the administrative panel.

Current systems since the circuit based G3rV10, still retain most of the features from the older models, but now support newer features such as IP Telephony, and mobility and unified messaging

Unified messaging

Unified Messaging is the integration of different electronic messaging and communications media technologies into a single interface, accessible from a variety of different devices....

.