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Overview of E&M Interfaces
Definition
E&M interfaces are used to receive and send recEive and transMit (E&M) data. During communication, E&M data is first encapsulated into pseudo wire emulation edge-to-edge (PWE3) packets, and then routers at both ends of a Multiprotocol Label Switching (MPLS) tunnel transparently forward the PWE3 packets through the MPLS tunnel.
Purpose
E&M interfaces are used for point-to-point (P2P) data transmission between E&M devices. For example, in the Air Traffic Control Communications System (ATCCS), E&M interfaces transmit voice signals between the Area Control Center (ACC) and stations for calls between traffic control personnel and people on airplanes.