AppleTalk Remote Access, or ARA, was a protocol stack that allowed AppleTalk to be run over modems. It became a fairly major product for Apple Computer in the early to mid-1990s when their first portable and laptop computers were available (and very popular). ARA slowly disappeared in the late 1990s when TCP/IP took over the vast majority of networking needs, notably remote access.

Most networking protocols have strong "layering" that separates the various jobs inside the protocol to different pieces of software. This allows them to be run on top of any hardware by replacing the lowest level software, the hardware drivers. For instance, IP can be made to run on a variety of Ethernet cards or even TokenRing with little effort. For slower speeds, like on modems, things become somewhat more difficult, as the protocols often have "invisible" assumptions about timing and performance that make it inefficient with very limited bandwidth.