Early Developments: SP1 SG-1 & SL-1
DMS Local End Offices
DMS Tandem Offices
List of Nortel Electronic & Digital Switches
Northern Telecom (formerly Northern Electric, later Nortel) originally licensed telephone switch technology from Western Electric in the United States. In the 1960s, Northern Telecom decides to strike out on their own to design and build their own line of telephone switching equipment.
Early Developments: SP1, SG-1 & SL-1
In the late 1960s, Northern Electric developed their own version of an electronically controlled analog telephone switch, similar to the Western Electric #1ESS. This switch, developed in 1969 was the SP1 (Stored Program 1) switch which used mini crossbar switches with electronic stored program control. Sub-varieites of this switch included the SP-1 2-Wire (local end office) and SP1 4-Wire (toll tandem). An update to this switch was the SP1E which used the NT40 processor.
Northern Electric and Bell Canada merged their research & development activities into Bell Northern Research (BNR) in 1971. By late 1972, Northern Telecom had its first electronically controlled analog switch on the market, the SG-1 (also known as the PULSE PBX or Private Branch eXchange). Within three years, some 6,000 had been sold. In 1975, Northern Telecom developed the SL-1, the first fully digital PBX system for businesses.
DMS Local End Offices
Becoming Northern Telecom in 1976, BNR continues its development of their groundbreaking work on a fully digital local central office. In 1977, Northern Telecom releases their first of their infamoux DMS (Digital Multiplex Switch) line of switching equipment with the DMS-10 digital central office switch for small communities. Though the DMS-10 was not the first developed and demonstrated digital central office switch, it was the first production local central office (Class 5) digital switch installed in the public switched telephone network.
Nortel DMS-10 switch (Photo:
Telcordia)
In 1979, Northern Telecom develops the DMS-100, a full-featured local end office digital switch to serve medium & large communities, supporting up to 100,000 lines.
Nortel
DMS-100 switch (Photo: Telcordia)
There are a number of sub-varieties and remote switching modules for the DMS series of local central office switch. See the List of Nortel Electronic & Digital Switches below for more details.
DMS Tandem Offices
The DMS line of digital switches also includes various tandem switches for various features. See the List of Nortel Electronic & Digital Switches below for more details.
List of Nortel Electronic & Digital Switches
The following is a list of Nortel’s electronic & digital switches. Note: this list does not include their new line of packet switching systems.
Early Electronic
Switches
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NE-1ESS (Licensed version of Western Electric #1ESS) (mid-1960s)
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SP1 (Electronic Stored Program Control using mini-bar switches) (1969)
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SP1 2-Wire (Local)
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SP1 4-Wire (Toll)
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SP1E (used NT40 processor)
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SG-1 (Electronic PBX) (1972)
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SL-1 (Digital PBX) (1975)
DMS-10 Local End Office Switches
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DMS-10 (Small local digital) (1977)
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DMS-10S (super small DMS-10 for very small exchanges <640 lines)
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DMS-10M (prepackaged DMS-10, a CDO in a "box")
DMS-100 Local End
Office Switches
DMS Tandems
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DMS-200 (Digital medium capacity long-haul toll digital)
(often combined with a DMS-100 – DMS-100/200)
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DMS-250 (Digital long-haul toll)
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DMS-300 (Digital international Gateway Switch)
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DMS-500 (Combined DMS-100/200/250)
Cellular Switches
The DMS family of "Supernode" switches are still being manufactured and are in widespread use throughout Canada, the United States and in many countries thoughout the world.
More details (off-site links)
Northern Electric History (Bell System Memorial)
Nortel History
Wikipedia List of Telephone Switches
Other
Modern Telephone
Switching System Pages
Telephone
Switching Systems - Main Page
Overview
of Modern ( Electronic & Digital Switching) Systems
Automatic
Electric Modern Switching Systems
Northern
Telecom (Nortel) Modern Switching Systems
TRW-Vidar
Switching Systems
Western
Electric Modern Switching Systems
Other
Modern Switching Systems of Note
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Page last modified December 20, 2008
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