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(IP Multimedia Subsystem)

IMS is a general-purpose, open industry standard for voice and multimedia communications over packet-based IP networks. It is a core network technology, that can serve as a low-level foundation for technologies like Voice over IP (VoIP), Push-To-Talk (PTT), Push-To-View, Video Calling, and Video Sharing. IMS is based primarily on SIP (session initiation protocol).

For users, IMS-based services enable person-to-person and person-to-content
communications in a variety of modes – including voice, text, pictures and
video, or any combination of these – in a highly personalized and controlled

IMS is a back-end, foundational technology that enables other services, not something a user would interact with directly.

For carriers, benefits of IMS include increased flexibility for carriers to offer new 3G services, and lower costs.

The idea behind IMS is to eventually move all voice and multimedia communication (mobile and fixed) to flexible, packet-based technologies derived from Internet protocols. It is intended to eventually replace all circuit-based technologies currently used in mobile networks, although it can easily be phased in, in a piecemeal fashion, integrating with circuit-based technologies and existing billing systems, etc.

Last updated Jul 5, 2022 by Rich Brome

Editor in Chief Rich became fascinated with cell phones in 1999, creating mobile web sites for phones with tiny black-and-white displays and obsessing over new phone models. Realizing a need for better info about phones, he started Phone Scoop in 2001, and has been helming the site ever since. Rich has spent two decades researching and covering every detail of the phone industry, traveling the world to tour factories, interview CEOs, and get every last spec and photo Phone Scoop readers have come to expect. As an industry veteran, Rich is a respected voice on phone technology of the past, present, and future.

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