Digital Multiplex System (DMS) is the name shared among several different
telephony
Telephony ( ) is the field of technology involving the development, application, and deployment of telecommunication services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is i ...
product lines from
Nortel Networks
Nortel Networks Corporation (Nortel), formerly Northern Telecom Limited, was a Canadian Multinational corporation, multinational telecommunications and data networking equipment manufacturer headquartered in Ottawa, Ontario, Canada. It was foun ...
for wireline and wireless operators. Among them are the DMS-1 (originally named the DMS-256) Rural/Urban
digital loop carrier, the DMS-10 telephone switch, the DMS SuperNode family of
telephone switch
telephone exchange, telephone switch, or central office is a telecommunications system used in the public switched telephone network (PSTN) or in large enterprises. It interconnects telephone subscriber lines or virtual circuits of digital syste ...
es (
DMS-100, DMS-200, DMS-250, DMS-300, DMS-500, DMS-GSP, DMS-MSC, DMS-MTX), and the S/DMS optical transmission system.
Exploratory development on the technology began at Northern Telecom's
Bell Northern Research Labs
Bell-Northern Research (BNR) was a telecommunications research and development company established In 1971 when Bell Canada and Northern Electric combined their R&D organizations. It was jointly owned by Bell Canada and Northern Telecom. BNR wa ...
in
Ottawa
Ottawa (, ; Canadian French: ) is the capital city of Canada. It is located at the confluence of the Ottawa River and the Rideau River in the southern portion of the province of Ontario. Ottawa borders Gatineau, Quebec, and forms the core ...
,
Ontario
Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central C ...
in 1971. The first
Class 5 switch, the DMS-10, began service on 21 October 1977 in
Fort White, Florida and the first
toll switch (Class 4), the DMS-200, entered service in 1979 in Ottawa. The DMS-10 was the first commercially successful Class 5 digital switch in the North American market and had a profound impact on the industry. Of the numerous digital switching products introduced in the North American telephone market in the late 1970s, only the Nortel DMS family is still in production. GENBAND (now
Ribbon Communications) acquired Nortel CVAS assets including the DMS line in 2011 and rolled it into its IP-based GENiUS platform. The GENiUS-750nt is the first product to include adaptive nano-tech compression and resynchronization modules from Ericsson, to replace the digital cross-connect (DCS) in place since the earliest DMS releases.
Previously, new technology had entered the telecommunications industry slowly, with the telephone companies
amortizing
Amortization or amortisation may refer to:
* The process by which loan principal decreases over the life of an amortizing loan
* Amortization (accounting), the expensing of acquisition cost minus the residual value of intangible assets in a system ...
equipment over periods as long as forty years.
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 tel ...
was intending to delay the introduction of
digital switching until the 1990s. The DMS, with its introduction of digital technology, changed the industry and became one of the antecedents that encouraged the growth of the Internet.
On October 16, 2006, Nortel received a special recognition award from Canada's
Telecommunications Hall of Fame for its role in pioneering digital communications with the Digital Multiplex System.
The DMS name arose from a designation for a switching matrix design that was developed in the exploratory phase of the project. The Digital Multiplexed Switch was selected as the basic switching design for the project. The product was intended as a successor for Nortel's first electronic switch, the
SP1, and was to be called the SP2. However the DMS acronym was mellifluous and was eventually (1975) adopted as the designation for the DMS-10 and DMS-100 family of products, with the "S" standing for "system" rather than "switch". It was then applied to the entire digital switching family as well as the DMS-1 family of Digital Transmission Concentrators.
DMS is favoured by many European
cable operators as the switching platform for their voice networks. The DMS-10 is widely used by rural wireline providers. DMS-100 and 200 switches are widely deployed throughout the U.S. and Canada by
Regional Bell Operating Companies,
Bell Canada
Bell Canada (commonly referred to as Bell) is a Canadian telecommunications company headquartered at 1 Carrefour Alexander-Graham-Bell in the borough of Verdun in Montreal, Quebec, Canada. It is an ILEC (incumbent local exchange carrier) in t ...
and
independent telephone companies
An independent telephone company was a telephone company providing local service in the United States or Canada that was not part of the Bell System organized by American Telephone and Telegraph. Independent telephone companies usually operated in ...
as well as the
US Military
The United States Armed Forces are the military forces of the United States. The armed forces consists of six service branches: the Army, Marine Corps, Navy, Air Force, Space Force, and Coast Guard. The president of the United States is the ...
. The DMS-250 is the backbone of a number of carriers' long-distance networks. The DMS-300 is an international gateway switch, and the DMS-500 is commonly deployed by
competitive local exchange carrier A competitive local exchange carrier (CLEC), in the United States and Canada, is a telecommunications provider company (sometimes called a " carrier") competing with other, already established carriers, generally the incumbent local exchange carrie ...
s because it combines DMS-100 and 250 capabilities.
DMS switches run a proprietary multitasking operating system known as SOS.
The user interface, called MAPCI, consists of a series of multi-level menus and is usually accessed from a connected VT100 compatible dumb terminal or terminal emulator. Each level or overlay performs different functions.
See also
*
List of telephone switches
This list of telephone switches is a compilation of telephone switches used in the public switched telephone network (PSTN) or in large enterprises.
American Digital Switching
* Centura 2000
Alcatel
This lists Alcatel switches before the merger w ...
References
{{reflist
External links
Nortel DMS product portfolio
Multiplexing
Telephone exchange equipment
Nortel products
Nortel