Meridian Norstar

The Meridian Norstar, later called Nortel Norstar was a small-office digital PBX introduced by Northern Telecom (now Avaya). It is based on the same internal design and instruction set as Nortel's earlier SL-1 and DMS systems, allowing it to support features such as integrated voice messaging (Meridian Mail), automatic call distribution and other features, but can support a total of up to 192 phones and has limited processing power. In the United Kingdom it is sold by British Telecom, rebadged as the BT Norstar.

With the advent of LSI ICs, also called integrated circuits in the 1980s, key telephone system design went from electro-mechanical parts to electronic or fully digital parts. The first key system developed by Northern Telecom in the early 1980s was the Vantage TDD system. Unlike the success of the SL1 system, the Vantage system did not catch with the business environment and the Meridian Norstar was developed as its replacement.

In 1988, Nortel developed the Meridian Norstar system. This system directly competed with the AT&T Merlin, ROLM Redwood, Executone/Isotec Hybrid systems, Toshiba DK Strata, and NEC hybrid systems. Unlike the earlier Vantage system, the Norstar went on to be one of the leading telephone systems in the world. It is visible worldwide with installations at major retail chains, educational environments, medical institutions, government facilities, and many places where key telephone systems are required.

The Norstar system went further than the other systems in similarity to a PBX system such as the Meridian SL-1/Meridian 1 system developed in the late 1980s as well. This allowed blurring the distinction of key telephone system versus PBX telephone system. Many features such as Direct Inward Dial, Caller ID, Automatic Call Distribution, and Call Accounting were designed off the larger Meridian 1 PBX, DMS-100 and Meridian SL-100 as opposed to being developed as an independent system.

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