DMS-100

The DMS-100 (Digital Multiplex System-100) is a digital telephone central office switch manufactured by Northern Telecom (later Nortel Networks). It was a widely deployed Class 5 local exchange switch, serving primarily residential and small business customers.

The DMS-100 utilized a fully digital architecture, moving away from earlier analog switching systems. This digital architecture offered improved reliability, efficiency, and the ability to support advanced features such as call waiting, call forwarding, and three-way calling.

The system was built around a modular design, allowing telecommunications companies to expand their switching capacity as needed. This modularity also facilitated upgrades and the integration of new technologies over time. The DMS-100 employed time-division multiplexing (TDM) to handle multiple calls simultaneously.

The DMS-100 also served as a platform for the introduction of various advanced services, including Custom Local Area Signaling Services (CLASS). Its architecture was fundamental in the transition to modern digital telecommunications networks. While Nortel Networks no longer supports the DMS-100, many legacy systems remain in operation worldwide, though they are increasingly being replaced by newer, IP-based technologies. The DMS-100 represents a significant milestone in the evolution of telecommunications switching technology.