The term postmodernism has been applied both to the era following modernity, and to a host of movements within that era (mainly in art, music, and literature) that reacted against tendencies in modernism.
A CSU/DSU (Channel Service Unit/Data Service Unit) is a hardware device about the size of an external modem that converts a digital data frame from the communications technology used on a local area network (LAN) into a frame appropriate to a wide-area network (WAN) and vice versa.he Data Service Unit (DSU) manages line control, and converts input and output between RS-232C, RS-449, or V.xx frames from the LAN and the time-division multiplexed (TDM) DSX frames on the T-1 line. The DSU manages timing errors and signal regeneration.
DSL stands for Digital Subscriber Line which provides digital data transmission over the wires of local telephone network. Originally DSL stands for Digital Subscriber Loop, but later on Digital Subscriber Line has been widely adopted as a more marketing-friendly term for ADSL, which is the most popular version of consumer-ready DSL.