Multimedia Engineering
  Chief Leschi Video

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Routing and Control

Composite Baseband Routing Switcher: The routing switcher (sometimes called a "crosspoint switcher" or "router") is the heart of the Chief Leschi video distribution system. All the multimedia sources connect to the inputs of the switch, usually through a source interface and always through a multiplexer. The routing switch is of a wideband design, allowing it to switch the baseband composite of video and audio simultaneously through one crosspoint. The outputs of the switcher feed transmitters which amplify and impedance match the signal to the twisted pair cable which delivers the signal to the classrooms. The switch is equipped with local manual controls and is a computer unto itself, but receives its commands through its connection to the system supervisor.


VME System Supervisor: The Vertically Modulated E-bus system supervisor is the brain of the Chief Leschi video distribution system. It is directly connected to most every piece of the system, and indirectly connected to everything else. At the classroom end, the system universal infra red remote control sends commands through the I.R. receiver to the classroom control panel which delivers these commands over a dedicated twisted pair, separate from the pair delivering the video/audio composite back to Headend where the supervisor is located. Any classroom equipped with a PC that is connected to the Chief Leschi LAN can communicate with the media management PC located in the Headend for content scheduling and source equipment assignment. The software also allows for emulation of the commands available on the hand held infra red remote control, so content can be commanded from the PC desktop if more convenient than using the remote itself. This is possible because the media management PC is connected to both the LAN and to the system supervisor. At the headend, the supervisor is connected to every source, either directly or through a source interface, enabling the commands from the classroom end to instantaneously control the source function, e.g. play, pause, stop, rewind or fast forward. The supervisor also connects to the baseband routing switcher, sending signal destination and source routing information to the switch's on board computer which implements crosspoint control.