ELECTRICAL ENGINEERING

The pantograph is typically, a single or double wire is used, with the return current running through the rails. Other types of current collectors include the bow collector and the trolley pole. pantograph  (or " pan " or " panto ") is an apparatus mounted on the roof of an electric  train ,  tram  or  electric bus [1]  to collect power through contact with an  overhead line . The term stems from the resemblance of some styles to the mechanical  pantographs  used for copying handwriting and drawings. The diamond-shaped, electric-rod pantograph of the Swiss  cogwheel  locomotive of the  Schynige Platte railway  in  Schynige Platte , built in 1911 Cross-arm pantograph of a  Toshiba EMU The pantograph is a common type of  current collector ; typically, a single or double wire is used, with the return current running through the  rails . Other types of current collectors include the  bow collector ...

  Networking is  the exchange of information and ideas among people with a common profession or special interest, usually in an informal social setting . Networking often begins with a single point of common ground. The layers are :  Layer 1—Physical;  Layer 2—Data Link;  Layer 3—Network;  Layer 4—Transport;  Layer 5—Session;  Layer 6—Presentation;  Layer 7—Application . The  Open Systems Interconnection model  ( OSI model ) is a  conceptual model  from the  International Organization for Standardization  (ISO) that "provides a common basis for the coordination of standards development for the purpose of systems interconnection." [2]  In the OSI reference model, the communications between a computing system are split into seven different abstraction layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application. The model partitions the flow of data in a communication system into sev...