النظام العالمي للاتصالات المتنقلة
ATM Adaptation Layer 2 (AAL2) is an ATM adaptation layer for Asynchronous Transfer Mode (ATM), used primarily in telecommunications; for example, it is used for the Iu interfaces in the Universal Mobile Telecommunications System, and is also used for transporting digital voice. The standard specifications related to AAL2 are ITU standards I.363.2 and I366.1.