Add-drop multiplexer Add-drop multiplexer An add-drop multiplexer (ADM) is an important element of an optical fiber network. A multiplexer combines, or multiplexes, several lower-bandwidth streams of data into a single beam of light. An "add-drop" multiplexer also has the capability to "add" one or more lower-bandwidth signals to an existing high-bandwidth data stream, and at the same time can extract or "drop" other low-bandwidth signals, removing them from the stream and redirecting them to some other network path. This is used as a local "on-ramp" and "off-ramp" to the high-speed network. ADMs can be used both in long-haul core networks and in
What Child Is This? of the Shepherds, who visited Jesus during his Nativity. The questions posed in the lyrics reflect what the shepherds were possibly pondering to themselves when they encountered him, with the rest of the carol providing a response to their questions. At the time he was writing the lyrics to "What Child Is This?" in 1865, William Chatterton Dix was working as the manager of an insurance company. He was afflicted by an unexpected and severe illness that resulted in him being bedridden and suffering from severe depression. His near-death experience brought about a spiritual renewal in him while he was