(Integrated Access Device) A device that multiplexes a variety of communications technologies in the customer's premises onto a single telephone line for transmission to the carrier. It also demultiplexes the incoming streams into their respective channels. Devices supporting various combinations (analog voice, DSL, ISDN, T1, etc.) are available. The term often refers to a device that deals only with DSL, mixing both voice and data over the DSL line. See VoDSL.