ATM (Asynchronous Transfer Mode)

ATM stands for Asynchronous Transfer Mode, was a networking technology that was designed to unify the transport of both circuit-switched traffic (like PDH and ISDN) as well as packet-switched traffic (like X.25, Frame Relay) over the seme physcial links and network.

The original trigger for ATM standardization in the late 1980s was to use it for the then-planned B-ISDN (Broadband Integrated Serviceds Digital Network). Ultimately, B-ISDN was never realized beyond trial networks, but ATM wide-area networks were built and used by (mostly) traditional telecommunications / telelphone companies as back-bones.

ATM was also used as the initial back-haul technology of cellular base stations in the 3G (WCDMA, UMTS) cellular networks (deployed in many countries between 2001 and 2005). Furthermore, traces of ATM can be found in early ADSL networks.

You can find our [so far rather limited] information at our ATM related wiki pages.